WO2011102299A1

WO2011102299A1 - Control device and projection-type image display device

Info

Publication number: WO2011102299A1
Application number: PCT/JP2011/052913
Authority: WO
Inventors: 史教水野; 直幸二村; 俊朗中莖; 善光野口
Original assignee: 三洋電機株式会社
Priority date: 2010-02-19
Filing date: 2011-02-10
Publication date: 2011-08-25
Also published as: JP2012008522A

Abstract

When manual focus adjustment operations are initiated by a user, focusing information is automatically projected and displayed on a screen. A projection unit (10) projects an image on a screen (300) via a focus lens (13). An imaging unit (30) images the screen. A manually operated focus-ring (15) is provided on the projection unit (10). A focus evaluation value calculation unit (42) acquires an image which has been imaged by the imaging unit (30), and calculates, as a focus evaluation value, a characteristic value which changes according to the focus state of the image projected on the screen. When the focus evaluation value changes, an evaluation value change detection unit (44) determines that the focus-ring (15) is being operated by a user. When it is determined that the focus-ring (15) is being operated, a focus adjustment assist unit (70) combines the focusing information, which is for supporting focus adjustment, with the image and projects and displays the result.

Description

Control device and projection display device

The present invention relates to a focus adjustment technique in a projection display apparatus.

Some projection-type image display devices that project images onto a screen (hereinafter referred to as projectors as appropriate) project information for assisting manual focus adjustment in which a user operates a focus ring. For example, Patent Document 1 discloses a liquid crystal projector that outputs a video signal of a focus adjustment pattern on a screen.

Japanese Unexamined Patent Publication No. 04-051227

In order to display the focus focusing information on the screen, in Patent Document 1 described above, the user needs to operate the adjustment switch to project the focus adjustment pattern. Without any special operation such as the operation of a dedicated button by the user or selection from a predetermined menu, the user's intention of manual focus adjustment is detected and focus focus information is projected and displayed on the screen. If you can, it is convenient.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for automatically projecting and displaying focus in-focus information on a screen when a user starts a manual focus adjustment operation. is there.

An aspect of the present invention provides a projection image that includes a projection unit that projects an image on a screen via a lens, an imaging unit that images the screen, and a focus adjustment unit that is provided in the projection unit and is manually operated. It is a control device mounted on the display device. This apparatus acquires a captured image captured by an imaging unit, calculates a characteristic value that changes according to a focus state of an image projected on a screen as a focus evaluation value, and a focus evaluation value An evaluation value change detection unit that determines that the focus adjustment unit is operated by the user and a focus focus for assisting focus adjustment when it is determined that the focus adjustment unit is operated. A focus adjustment assist unit that projects and displays information together with the image.

Another aspect of the present invention is a projection display apparatus. This apparatus includes a projection unit that projects an image on a screen via a lens, an imaging unit for imaging the screen, and the control unit described above.

According to the present invention, focus focus information can be projected and displayed on the screen at the start of a manual focus adjustment operation by the user.

It is a figure which shows the positional relationship of the projection type video display apparatus concerning one Embodiment of this invention, and a screen. It is a figure which shows the structure of the projection type video display apparatus concerning one Embodiment. It is a flowchart explaining operation | movement of a video signal evaluation part. It is a figure explaining the relationship between the change of an input signal evaluation value, and the state of a focus assist function. It is a flowchart explaining operation | movement of a focus evaluation part. It is a figure explaining the relationship between the change of a focus evaluation value, and the state of a focus assist function. It is a figure which shows typically the function structure of the projection type video display apparatus concerning 2nd Embodiment of this invention. FIG. 8A is a diagram illustrating an example of a relationship between a zoom operation detection image projected on a screen and an imaging range of an imaging unit. FIG. 8B is a diagram showing another example of the relationship between the zoom operation detection image projected on the screen and the imaging range of the imaging unit. It is a figure which shows an example of the fluctuation | variation of the focus evaluation value at the time of focus adjustment. FIG. 10A is a diagram illustrating an example of a graph at the start of focus adjustment. FIG. 10B is a diagram illustrating an example of a graph in a case where the focus evaluation value is smaller than the maximum value in the period in which the target value to be taken as the focus evaluation value is not detected. FIG. 10C is a diagram illustrating an example of a graph in the case where the focus evaluation value decreases in the period after the target value to be taken as the focus evaluation value is detected. FIG. 10D is a diagram illustrating an example of a graph in the case where the focus evaluation value increases in a period after the target value to be taken as the focus evaluation value is detected. It is a figure which shows the table with which the combination of the focus evaluation value and target value, and the display color of focus state information were matched. It is a figure which shows the state transition of the display color of focus state information. It is a flowchart which mainly shows the flow of a process of the control part based on 2nd Embodiment. FIG. 14A is a diagram showing a pattern image mainly used for focus adjustment. FIG. 14B is a diagram illustrating an example of a combination of a pattern image used for focus adjustment and a pattern image used for zoom operation detection. It is a figure which shows the positional relationship of the projection type video display apparatus concerning 3rd Embodiment of this invention, and a screen. It is a figure which shows an example of the captured image imaged by the imaging part in the positional relationship shown in FIG. It is a figure which shows the structure of the projection type video display apparatus concerning 3rd Embodiment. It is a figure which shows a mode that a detection area | region is set in the screen area | region in the captured image which concerns on 3rd Embodiment. It is a figure for demonstrating an example of the setting method of the detection area which concerns on 3rd Embodiment. It is a figure for demonstrating the determination process of the focus position of a focus lens. It is a figure which shows the structure of the projection type video display apparatus concerning 4th Embodiment of this invention. It is a figure which shows a mode that a detection area | region is set within the screen area | region in the captured image which concerns on 4th Embodiment. It is a figure which shows a mode that a detection area | region is moved to the area | region containing any corner | angular part of a screen area | region. It is a figure which shows the structure of the projection type video display apparatus concerning 5th Embodiment of this invention. It is a figure for demonstrating trapezoid distortion correction. FIG. 25A shows vertical trapezoidal distortion correction, and FIG. 25B shows horizontal trapezoidal distortion correction. It is a figure which shows a mode that the test pattern for trapezoid distortion detection is reflected in the screen area | region in the captured image which concerns on 5th Embodiment. It is a figure for demonstrating four-point correction | amendment.

First Embodiment FIG. 1 is a diagram showing a positional relationship between a projection display apparatus 200 and a screen 300 according to a first embodiment of the present invention. The projection display apparatus 200 according to the first embodiment includes an imaging unit 30 for photographing the direction of the screen 300. The imaging unit 30 is installed such that the optical axis center thereof and the optical axis center of the projection light projected from the projection display apparatus 200 have a parallel relationship, for example. In FIG. 1, the screen 300 faces the projection display apparatus 200.

The projection display apparatus 200 performs focus adjustment by manually moving a focus ring provided in front of the lens. In order to assist this focus adjustment, the projection display apparatus 200 projects and displays focus focusing information on the screen 300. The user can adjust the focus appropriately by moving the focus ring while referring to the focus focusing information.

FIG. 2 is a diagram showing a configuration of the projection display apparatus 200. As shown in FIG. The projection display apparatus 200 includes a projection unit 10, an imaging unit 30, and a control unit 100. The control unit 100 includes a focus evaluation unit 40, a video signal evaluation unit 50, a focus target calculation unit 60, a focus adjustment assist unit 70, a video signal setting unit 82, and an image memory 84.

The configuration of the control unit 100 can be realized in terms of hardware by a CPU, memory, or other LSI of an arbitrary computer, and can be realized in terms of software by a program loaded in the memory. Depicts functional blocks realized by. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

Projection unit 10 projects an image on screen 300. The projection unit 10 includes a light source 11, a light modulation unit 12, and a focus lens 13. As the light source 11, a halogen lamp having a filament-type electrode structure, a metal halide lamp having an electrode structure for generating arc discharge, a xenon short arc lamp, a high-pressure mercury lamp, an LED lamp, or the like can be employed.

The light modulator 12 modulates the light incident from the light source 11 in accordance with the video signal set by the video signal setting unit 82. For example, a DMD (Digital Micromirror Device) can be used as the light modulator 12. The DMD includes a plurality of micromirrors corresponding to the number of pixels, and generates desired video light by controlling the direction of each micromirror according to each pixel signal.

The focus lens 13 adjusts the focal position of the light incident from the light modulator 12. The focus lens 13 is provided with a focus ring 15, and the lens position is moved on the optical axis by manually rotating the focus ring. The image light generated by the light modulation unit 12 is projected onto the screen 300 via the focus lens 13. Any device other than the focus ring may be used as long as the lens position is moved on the optical axis.

The imaging unit 30 captures the screen 300 and a projected image projected on the screen 300 as a main subject. The imaging unit 30 includes a solid-state imaging device 31 and a signal processing circuit 32. As the solid-state imaging device 31, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, a CCD (Charge Coupled Devices) image sensor, or the like can be employed. The signal processing circuit 32 performs various signal processing such as A / D conversion and conversion from the RGB format to the YUV format on the signal output from the solid-state imaging device 31, and outputs the signal to the control unit 100.

The focus target calculation unit 60 acquires the video signal being projected and displayed on the screen from the video signal setting unit 82. Then, an evaluation value of the input video signal is calculated by performing the same calculation as that of the focus evaluation value calculation unit 42 described later. Similar to the focus evaluation value calculation unit 42, the calculation may be performed on the entire image, or may be performed for each divided area in the image.

The calculated evaluation value of the input video signal is used as a target value for the focus degree. Therefore, the evaluation value of the input video signal is sent to the focus adjustment assist unit 70. Then, when a focus assist function described later is on, it is superimposed and displayed on the screen together with the focus evaluation value for the captured image as focus in-focus information. The user can obtain an indication of the focus degree of focus by comparing the evaluation value of the input signal displayed as the focus focusing information with the focus evaluation value for the captured image.

Instead of displaying the evaluation value of the input signal and the focus evaluation value for the captured image, or together with this, the evaluation value representing the focus degree of focus is calculated and displayed using both evaluation values. It may be.

The focus adjustment assist unit 70 sets the focus assist function to a standby state in response to an instruction from the video signal evaluation unit 50. Then, in accordance with an instruction from the focus evaluation unit 40, the focus assist function is turned on or off.

Here, the “focus assist function” is a function for superimposing and displaying focus in-focus information for assisting focus adjustment by manual operation of the focus ring as at least a part of the projection screen on the screen. In the present embodiment, the start of the manual focus adjustment by the user is detected and the focus focus information is superimposed and displayed, and the end of the manual focus adjustment is detected and the display of the focus focus information is ended. Also, the video displayed together with the focus focusing information may use the video signal as it is, or may display a focus-dedicated pattern.

The focus focusing information is a focus evaluation value and a focus target value (that is, an evaluation value of the input video signal) of the captured image. Thereby, manual adjustment of the focus ring can be assisted.

The video signal evaluation unit 50 acquires the video signal being projected and displayed on the screen from the video signal setting unit 82. The video signal evaluation unit 50 includes an input signal evaluation value calculation unit 52 and an input signal evaluation value determination unit 54.

The input signal evaluation value calculation unit 52 calculates an input signal evaluation value for determining whether or not to set the focus assist function to the standby state. As the input signal evaluation value, any characteristic value that changes depending on the presence or absence of motion in the video, such as a high-frequency component, contrast information, and luminance information of the video signal can be used. Any method can be used to calculate the high-frequency component or contrast from the video signal. The input signal evaluation value may be calculated from the entire screen, or may be calculated for each region by dividing the screen into a plurality of regions. The input signal evaluation value is preferably calculated at a predetermined time interval or every predetermined number of frames.

The input signal evaluation value determination unit 54 determines whether or not to standby the focus assist function based on the change in the input signal evaluation value. Based on the input signal evaluation value, if it is determined that the video signal being projected and displayed on the screen is a moving image or a still image has been switched, manual focus adjustment is difficult, so the focus assist function remains off. And When it is determined that the video signal being projected and displayed on the screen is a still image based on the input signal evaluation value, the focus adjustment assist unit 70 is instructed to set the focus assist function to the standby state.

The focus evaluation unit 40 acquires a captured image from the signal processing circuit 32. The focus evaluation unit 40 includes a focus evaluation value calculation unit 42 and an evaluation value change detection unit 44.

The focus evaluation value calculation unit 42 calculates a focus evaluation value for detecting the start and end of manual focus adjustment by the user. As the focus evaluation value, any characteristic value that changes according to the focus state of the image projected on the screen, such as a high-frequency component of the captured image, contrast information, and luminance information, can be used. Any method can be used to calculate the high-frequency component or contrast from the captured image. The focus evaluation value is calculated for each area from the entire captured image or by dividing the captured image into a plurality of areas. The focus evaluation value is preferably calculated at a predetermined time interval or every predetermined number of frames.

The evaluation value change detection unit 44 detects the start of manual focus adjustment by the user based on the focus evaluation value when the focus assist function is in the standby state. Specifically, when there is no change in the focus evaluation value, the standby state of the focus assist function is maintained assuming that the focus ring is not moved. When only the focus evaluation value of a part of the plurality of areas changes, it is determined that a person or hand has crossed the front of the projector, and the standby state of the focus assist function is maintained. When the focus evaluation value changes in the same increase / decrease direction in all areas, it is determined that the focus ring is moved, and the focus adjustment assist unit 70 is instructed to turn on the focus assist function.

Furthermore, the evaluation value change detection unit 44 detects the end of manual focus adjustment by the user based on the focus evaluation value. In other words, after the focus assist function is turned on, if there is no change in the focus evaluation value for a predetermined period (for example, 5 to 10 seconds), it is determined that the adjustment by the focus ring has been completed and the focus assist function is turned off. The focus adjustment assist unit 70 is instructed to

Note that when the focus ring 15 is moved, the angle of view of the projected image changes slightly. Therefore, it is preferable to set a certain amount of allowable change in the focus evaluation value.

Also, if the projected image has a pattern only on a part of it and the other part is a solid image, the degree of change in the focus evaluation value of a part of the area during manual adjustment using the focus ring In some cases, a phenomenon may occur in which the degree of change in the focus evaluation value in other regions becomes larger. Even in such a case, since the increase / decrease direction of the focus evaluation value in all the regions is the same (that is, increases in all regions or decreases in all regions), it is possible to detect the start of manual adjustment by the focus ring. There is no change.

The image memory 84 holds image data to be projected on the screen 300. The image data is supplied from a video reproduction device such as a personal computer or a DVD player via an external interface (not shown). The video signal setting unit 82 sets a video signal based on the image data held in the image memory 84 in the light modulation unit 12.

In the projection display apparatus 200 according to the present embodiment, the start and end of manual focus adjustment using the focus ring 15 by the user is detected based on the following characteristics.

That is, when the focus ring is moved, the focus state of the entire screen often changes, and the focus state of only a part of the screen rarely changes greatly. Further, the focus state changes relatively slowly, and there is a steep change only in the vicinity of the focus. On the other hand, when a person or hand crosses in front of the projector, the focus state changes greatly only with a part of the screen. In addition, when the video signal is switched, the focus state changes abruptly.

Based on such characteristics, the projection display apparatus 200 captures an image projected and displayed on the screen with a camera, and determines whether the focus ring is moved based on a change in the focus evaluation value calculated from the captured image. No, that is, the start and end of manual focus adjustment are determined.

FIG. 3 is a flowchart for mainly explaining the operation of the video signal evaluation unit 50. First, the input signal evaluation value calculation unit 52 acquires a video signal being projected and displayed from the video signal setting unit 82 (S10), and calculates an input signal evaluation value for the entire screen or for each divided area (S12). When there is no change in the input signal evaluation value within a predetermined period (for example, several seconds) (N in S14), it is determined that the video signal is a still image, and the focus adjustment assist unit 70 is set so that the focus assist function is in a standby state. (S20). If there is a change in the input signal evaluation value (Y in S14), it is determined that the video signal is a moving image or a still image is switched, and the focus assist function is kept off (S16). Thereafter, when no change is observed in the input signal evaluation value within a predetermined period (Y in S18), it is determined that the video signal has been switched to a still image, and the focus adjustment assist unit is set so that the focus assist function is in a standby state. 70 is instructed (S20).

FIG. 4 is a diagram for explaining the change in the input signal evaluation value and the state of the focus assist function. FIG. 4A shows the time change of the input signal evaluation value, and FIG. 4B shows the state of the focus assist function.

4A, there is no change in the input signal evaluation value in the periods t1, t3, and t5. Therefore, during this period, it is determined that the video signal is a still image, and the focus assist function is set to the standby state. In the period t2, the input signal evaluation value changes rapidly. During this period, it is determined that the still image has been switched, and the focus assist function is turned off. In the period t4, the input signal evaluation value in each region varies randomly. During this period, it is determined that the video signal is a moving image, and the focus assist function is turned off.

FIG. 5 is a flowchart for mainly explaining the operation of the focus evaluation unit 40. First, it is determined whether or not the focus assist function is in a standby state (S50). In the standby state (Y in S50), the focus evaluation value calculation unit 42 acquires a captured image and calculates a focus evaluation value for each divided area (S52). The evaluation value change detection unit 44 observes the focus evaluation value within a predetermined period (for example, several seconds) (S54). If no change in the focus evaluation value is observed in all areas, or there is a change in the focus evaluation value in an area below a predetermined ratio (Y in S54), the standby state of the focus assist function is maintained (S56). ). When a change in the focus evaluation value is observed in an area of a predetermined ratio or more (N in S54), it is determined that manual focus adjustment has been started, and the focus adjustment assist unit 70 is instructed to turn on the focus assist function. (S58). In response to this, focus information is projected and displayed on at least a part of the projection screen.

The evaluation value change detection unit 44 determines that the focus ring is being moved while the focus evaluation value is changing (N in S60). When no change in the focus evaluation value is observed for a predetermined period (Y in S60), it is determined that the manual focus adjustment by the user has ended, and the focus adjustment assist unit 70 is instructed to turn off the focus assist function ( S62). In response to this, the focus focusing information disappears from the projection screen.

In S52 to S54 described above, a focus evaluation value is calculated for each of the divided areas, and the focus evaluation value does not change in all the areas, or the focus evaluation value changes only in a part of the areas. When determining whether or not there is, the evaluation value change detection unit 44 may divide the screen into a plurality of regions and refer to the input signal evaluation values calculated for each region. In this way, the focus evaluation value of the captured image can be determined while referring to the local characteristics of the input signal, so that the determination accuracy can be improved.

FIG. 6 is a diagram for explaining the change of the focus evaluation value and the state of the focus assist function. FIG. 6A shows the temporal change of the focus evaluation value, and FIG. 6B shows the state of the focus assist function.

In the following explanation, it is assumed that the focus assist function is in the standby state. In FIG. 6A, in the period t6, since the focus evaluation value does not change, the standby state is maintained. In the period t7, since the focus evaluation value of only a part of the region fluctuates, it is not regarded as a focus ring operation, and the standby state of the focus assist function is maintained. In the period t8, since the focus evaluation values of all the regions are changed, it is determined that the focus ring is moved, and the focus assist function is turned on. In response to this, focus information is projected and displayed on at least a part of the projection screen. Thereafter, since the focus change value has not changed over the predetermined period D, it is determined that the operation of the focus ring has been completed, and the focus assist function is turned off in the period t9. In response to this, the focus focusing information disappears from the projection screen.

As described above, according to the projection display apparatus according to the first embodiment, it can be determined whether or not the user manually moves the focus ring. When the focus ring is moved by the user, the focus focus information is automatically superimposed on the projection screen, and when the focus ring operation is stopped, the focus focus information disappears from the projection screen. Therefore, the user does not need to operate a dedicated button or select a function from the menu screen in order to display the focus focusing information.

The first embodiment described above is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. It is understood.

In the first embodiment, the focus evaluation value is calculated for the entire captured image or for each divided region. Instead, the focus evaluation value calculation unit may detect a screen area from the captured image by a well-known method, and calculate the focus evaluation value only within the screen area. As a result, the focus evaluation value is calculated only within the screen where the focus is changed by the operation of the focus ring, and therefore the focus ring operation can be detected more accurately.

An inclination determination unit that determines whether the screen 300 is inclined based on the captured image may be provided. When it is determined that the screen is inclined, the focus point when the focus ring is operated varies depending on the position in the screen. In this case, it is preferable that the focus evaluation value calculation unit calculates the focus evaluation value only in a region closer to the back focus in the screen.

Second embodiment.
In a projection display apparatus, in order to automatically perform various adjustments necessary for display, a motor, its control device, and the like are required, which can increase the cost of the apparatus. On the other hand, manually adjusting the focus ring to adjust the focus can be a complicated task for the user. Therefore, if the current focus state can be projected and displayed on the screen when the user manually adjusts the focus, the convenience of the focus adjustment can be improved while suppressing the cost of the apparatus.

In the second embodiment of the present invention, it is an object to provide auxiliary means when the user performs a manual focus adjustment operation.

The outline of the second embodiment will be described. The projection display apparatus according to the second embodiment renews the focus adjustment auxiliary information presented to the user when the zoom operation by the user is detected.

FIG. 7 is a diagram schematically illustrating a functional configuration of the projection display apparatus 1200 according to the second embodiment. The projection display apparatus 1200 includes a projection unit 10, an imaging unit 30, and a control unit 1100. The control unit 1100 includes a focus evaluation value calculation unit 142, a zoom operation detection unit 144, a focus state information setting unit 150, a video signal setting unit 82, and an image memory 84. The projection unit 10, the imaging unit 30, the video signal setting unit 82, and the image memory 84 have the same configuration as that described with reference to FIG.

The projection unit 10 includes a light source 11, a light modulation unit 12, a lens 13, a zoom ring 14, and a focus ring 15. The lens 13 adjusts the focal length of the light incident from the light modulation unit 12 and adjusts the focus. Although not shown, the lens 13 includes a zoom lens for moving the focal length and a focusing lens for adjusting the focus. The lens 13 is provided with a zoom ring 14 and a focus ring 15. When the user manually rotates the zoom ring 14 or the focus ring 15, the lens position moves on the optical axis. The image light generated by the light modulation unit 12 is projected onto the screen 300 via the lens 13. Note that any device other than the zoom ring 14 and the focus ring 15 may be used as long as the lens position is moved on the optical axis.

The focus evaluation value calculation unit 142 obtains a captured image captured by the imaging unit 30 and performs image analysis, thereby using a characteristic value that changes according to the focus state of the video adjusted by the focus ring 15 as a focus evaluation value. calculate. The focus evaluation value is used for the focus assist function.

The “focus assist function” is a function for superimposing and displaying focus state information for assisting focus adjustment by manual operation of the focus ring 15 as at least a part of the projection screen on the screen 300. Details of the focus state information will be described later. In the second embodiment, the focus state information is superimposed and displayed during manual focus adjustment by the user. In addition, as the video displayed together with the focus state information, the video signal may be used as it is, or a focus-dedicated pattern may be displayed.

As the focus evaluation value, any characteristic value that changes in accordance with the focus state of the image projected on the screen, such as a high-frequency component of the captured image, contrast information, and luminance information, can be used. In order to calculate a high-frequency component or contrast from a captured image, any image analysis method such as Fourier transform, multi-resolution analysis, edge extraction, or the like can be used. The focus evaluation value is calculated for each area from the entire captured image or by dividing the captured image into a plurality of areas. The focus evaluation value is preferably calculated at a predetermined time interval or every predetermined number of frames.

The zoom operation detection unit 144 determines whether or not the zoom ring 14 is operated by the user by acquiring a captured image captured by the imaging unit 30 and analyzing the image. This can be realized, for example, by extracting an edge component in the image and detecting an increase / decrease in the edge component.

FIG. 8 is a diagram for explaining an example of the principle of detecting the presence or absence of a zoom operation. The example shown in FIG. 8 is an example of a case where a zoom operation detection video is projected on the screen 300 and the video is acquired and analyzed in order to detect a zoom operation by the user. FIG. 8A is a diagram illustrating an example of a relationship between a zoom operation detection image projected on the screen 300 and an imaging range of the imaging unit 30. FIG. 8A shows that the vertical stripe pattern 500 is projected on the screen 300 and the imaging unit 30 images the imaging range 400.

FIG. 8B is a diagram illustrating another example of the relationship between the zoom operation detection image projected on the screen 300 and the imaging range of the imaging unit 30. Compared to FIG. 8A, FIG. 8B projects the pattern 500 in a reduced size due to the influence of the zoom operation by the user. Note that the size of the screen 300 and the imaging range 400 of the imaging unit 30 are the same as in FIG.

The zoom operation detection unit 144 detects the presence or absence of a zoom operation by counting the number of vertical stripes projected on the screen 300 and examining the fluctuations. For example, in the example shown in FIG. 8A, seven black vertical stripes are projected on the screen 300. It is assumed that the user operates the zoom ring 14 to reduce the pattern 500 and the state shown in FIG. In the example shown in FIG. 8B, the number of black vertical stripes projected on the screen 300 varies from 7 to 9. As described above, the zoom operation detection unit 144 can detect the presence or absence of the zoom operation by counting the number of vertical stripes projected on the screen 300 and examining the variation thereof. Counting the number of black vertical stripes can be realized by using, for example, general edge extraction processing and threshold processing.

The focus state information setting unit 150 sets focus state information displayed on the screen 300 as the above-described focus assist function. The focus state information setting unit 150 includes a focus evaluation value storage unit 152, a focus state determination unit 154, and a graph database 156. Hereinafter, the configuration of the focus state information setting unit 150 will be described with reference to FIGS. 9, 10, 11, and 12.

FIG. 9 is a diagram showing an example of a change in focus evaluation value during focus adjustment. In the example shown below, it is assumed that the focus evaluation value increases as the focus state is improved.

It is assumed that the projection display apparatus 1200 is turned on at time t ₀ and an image is displayed on the screen 300. In this state, the focus is not normally achieved, and the captured image captured by the imaging unit 30 is a blurred image with a small number of high frequency components. Between time t ₀ of t ₁ is not made adjustment of the focus, the focus evaluation value does not change. The focus evaluation value storage unit 152 stores f ₀ acquired from the focus evaluation value calculation unit 142 as an initial value of the focus evaluation value. Focus evaluation value storage unit 152 also stores the f ₀ as a provisional maximum value f _m of the focus evaluation value. The “provisional maximum value f _m ” is the maximum value of the focus evaluation value calculated by the focus evaluation value calculation unit 142 in the past.

The user initiates the adjustment of the focus at the time t _1. From time t ₁ to t ₂ , the user makes an adjustment in the wrong direction, that is, the direction in which the focus is less suitable, and thus the focus evaluation value f becomes lower than the initial value f ₀ . In the following, when notation is not added and it is simply written as f, it represents the current value of the focus evaluation value. The focus evaluation value storage unit 152 stores the current value f of the focus evaluation value separately from the initial value f ₀ of the focus evaluation value.

In time t _2, the user initiates a focus adjustment in the right direction. Current value f of the focus evaluation value increases until the initial value f ₀ at time t _3. Time t ₃ after, since the focus evaluation value f continues to rise, the focus evaluation value storage unit 152 every time updating the provisional maximum value f _m with the value of the focus evaluation value f.

As a result of the user's continued focus adjustment in the correct direction, the focus evaluation value f takes the peak value f ₁ at time t ₄ and then decreases. This is because if the focus adjustment continues even though the focus has been achieved, the image will be out of focus and the image will be blurred. Then at time t ₅ the user returns the focus adjustment again focus evaluation value f at time t ₆ is the peak value f _1. Adjust the focus of the at time t ₆ is terminated.

The focus state determination unit 154 calculates an average value f _a of focus evaluation values calculated in the past, and stores the result in the focus evaluation value storage unit 152. The focus state determination unit 154 also detects the peak value f ₁ of the focus evaluation value described above and stores it in the focus evaluation value storage unit 152 as the maximum value f _M of the focus evaluation value. Specifically, the focus state determination unit 154 tracks the amount of change in the focus evaluation value, and sets the focus evaluation value f when the amount of change changes from increasing to decreasing as the maximum value f _M of the focus evaluation value. Since the maximum value f _M of the focus evaluation value is the focus evaluation value in a state where the focus suits, becomes a target value to be taken by the focus evaluation value.

The magnitude relationship between the current value f of the focus evaluation value and the target value of the focus evaluation value is the above-described focus state information. Therefore, the focus state determination unit 154 determines the display mode of the graph in order to express the focus state information as a graph having a color indicating the degree of focus.

FIG. 10 is a diagram illustrating an example of a graph representing focus state information. FIG. 10A is a diagram illustrating an example of a graph at the start of focus adjustment, and is a graph of a period from t ₀ to t ₁ in FIG. The graph is projected over the image projected on the screen. A rectangle whose longitudinal direction is the horizontal direction with respect to the image is a graph, and the focus evaluation value and the memory of the graph are associated with each other. The color of the graph and the area with the color according to the change of the focus evaluation value The area increases or decreases. In the example of FIG. 10A, a color is attached to a three-quarter region of the graph. In the following, in FIG. 10, a region represented by an oblique diagonal line represents a yellow region, and a region represented by an oblique lattice represents a red region. Also, in FIG. 10, the memory width of the graph is larger at the left end of the graph than the right end, and the colored area greatly increases or decreases. On the other hand, the colored area increases or decreases finely at the right end of the graph. Thereby, as the focus approaches the correct state, the user can grasp the detailed focus state, which is advantageous in that convenience is improved.

FIG. 10B illustrates the above-described maximum focus evaluation value f _M , that is, the focus evaluation value f is smaller than the provisional maximum value f _m during a period in which the target value to be taken by the focus evaluation value is not detected. is a diagram showing an example of a graph in a case, a graph of the period t ₂ from t ₁ in FIG. The length of the yellow colored region in the graph changes according to the focus evaluation value f. Although not shown in the figure, the focus evaluation value f continues to increase during the period in which the maximum value of the focus evaluation value f _M described above, that is, the target value to be taken as the focus evaluation value is not detected (t ₃ in FIG. 9). period _{t 4)} from, the same graph as the example of FIG. 10 (a).

FIG. 10C is a diagram illustrating an example of a graph when the focus evaluation value f decreases in a period after the target value to be taken by the focus evaluation value f is detected. From t ₄ to t in FIG. ₅ is a graph of a period of ₅ . The display color of the colored area indicating the three-quarter area of the graph changes from yellow to red.

FIG. 10D is a diagram illustrating an example of a graph when the focus evaluation value f increases in the period after the target value to be taken by the focus evaluation value f is detected. From t ₅ to t in FIG. It is a graph of ₆ periods. Nearly the entire area of the graph is yellow. Although not shown, when the focus evaluation value f is equal to the maximum value f _M which is the target value, the whole area of the graph becomes a blue color, to notify that the focus adjustment is completed the user. As described above, the focus state information serves as auxiliary means when the user performs a manual focus adjustment operation.

FIG. 11 is a diagram showing a table in which combinations of focus evaluation values and target values are associated with display colors and display amounts of focus state information. The table shown in FIG. 11 is stored in the graph database 156, and the focus state determination unit 154 determines focus state information to be displayed with reference to this table.

Specifically, the focus state determination unit 154 acquires the focus evaluation value stored in the focus evaluation value storage unit 152 and calculates the change thereof. First, examine the magnitude relation between the current value f of the focus evaluation value and the average value f _a, is determined increase in the table shown in FIG. 11, constant, and it is in any state of descent. Then the focus state determination unit 154, the maximum value f _M which is the target value of the focus evaluation value to determine whether it has been detected. If the maximum value f _M is undetected, the magnitude relationship of the focus state determination unit 154 and the current value f provisional maximum value f _m and the focus evaluation value, and the initial value f ₀ of the focus evaluation value and the provisional maximum value f _m Investigate the size relationship.

When the maximum value f _M is detected, the focus state determination unit 154 determines the magnitude relationship between the maximum value f _M and the current value f of the focus evaluation value, and the initial value f ₀ of the focus evaluation value and the maximum value f _M. Examine the magnitude relationship. By examining the above, the focus state determination unit 154 can determine the focus state information to be displayed from the table stored in the graph database 156. Note that whether or not the maximum value f _M is detected, achieved by examining the value of the flag (MaxFlag) shown is secured in the work memory (not shown), whether or not the maximum value f _M is detected it can. This flag is initialized to 0, the focus state determination unit 154 is set to 1 when detecting the maximum value f _M.

FIG. 12 is a diagram illustrating the state transition of the display color of the focus state information. In FIG. 12, possible states of the display color of the focus state information are displayed by a combination of ST (abbreviation of State) meaning a state and a number. When the control unit 1100 is activated and the focus evaluation value calculation unit 142 calculates the focus evaluation value f, the evaluation value initialization state ST10 is entered. In the evaluation value initialization state ST10, the focus evaluation value calculation unit 142 evaluation value initially calculated is stored in the focus evaluation value storage unit 152 as a provisional maximum value f _m and the initial value f _0.

When the provisional maximum value f _m and the initial value f ₀ is stored in the focus evaluation value storage unit 152, it shifts to the yellow display state ST12. It is possible to shift from the yellow display state ST12 to the yellow display state ST12 itself, the red display state ST16, the blue display state ST14, the graph erasing state ST20, and the zoom change detection state ST18.

The numbers surrounded by circles in FIG. 12 correspond to the numbers surrounded by circles in the table of FIG. For example, the transition from the yellow display state ST12 to the blue display state ST14 is performed in the following two cases. That is, the current value f is greater than the average value f _a of the evaluation value of the focus has been detected maximum value f _M, or if the current value f and the maximum value f _M is equal to, or focus evaluation value equal to the current value f and the average value f _a have been detected maximum value f _M, which is when the current value f and the maximum value f _M is equal.

When the user operates the zoom ring 14, the focus evaluation value varies because the size of the image projected on the screen 300 changes. Therefore, the provisional maximum value f _m and the maximum value f _M can not make sense found so far. Therefore, when the zoom operation detection unit 144 detects that the zoom ring 14 is operated by the user, the zoom change detection state is detected from the yellow display state ST12, the blue display state ST14, and the red display state ST16. Move on to ST18. As a result, operations such as initialization of the focus evaluation value f are performed again. This is advantageous in that the reliability of the focus evaluation value can be ensured.

In the yellow display state ST12, the blue display state ST14, and the red display state ST16, when the user forcibly ends the focus adjustment, the graph adjustment state ST20 is entered and the focus adjustment ends.

FIG. 13 is a flowchart mainly showing a processing flow of the control unit 1100 according to the second embodiment. The processing in this flowchart starts when, for example, the projection display apparatus 1200 is turned on and the imaging unit 30 captures an image projected on the screen 300.

The focus evaluation value calculation unit 142 obtains a captured image captured by the imaging unit 30 and performs image analysis, thereby using a characteristic value that changes according to the focus state of the video adjusted by the focus ring 15 as a focus evaluation value. The calculated value is stored in the focus evaluation value storage unit 152 (S110). The focus state determination unit 154 acquires the focus evaluation value stored in the focus evaluation value storage unit 152 and calculates the change (S112).

Focus state determination unit 154 of the display color of the focus state information, the magnitude relationship between the current focus evaluation value f and the average value f _a, the maximum value f _M or interim maximum value f _m and the current focus evaluation value f Focus state information to be displayed is determined by referring to a table in which the magnitude relationship and the combination of the magnitude relationship between the maximum value f _M or the provisional maximum value f _m and the initial value f ₀ are associated (S114). . The video signal setting unit 82 acquires the focus state information from the focus state determination unit 154 as a graph having a color indicating the degree of focus, and transmits the graph to the projection unit 10 to update the graph displayed on the screen 300 ( S116).

If the current focus evaluation value f and the maximum value f _M focus adjustment without is not completed match (S118 of N), the process is repeated from step S10 described above S16. If the current focus evaluation value f and the maximum value f _M focus adjustment is completed match (S118 of Y), the focus state determination unit 154 notifies to erase the graph to the video signal setting unit 82 Graph Is deleted (S120). When the graph is deleted in step S20, the processing in this flowchart ends.

Operation with the above configuration is as follows. The user projects an image on the screen 300 using the projection display apparatus 1200 according to the second embodiment, and operates the focus ring 15 to adjust the focus. The focus state determination unit 154 analyzes the focus evaluation value calculated by the focus evaluation value calculation unit 142 and stored in the focus evaluation value storage unit 152, and projects the current focus state onto the screen 300 as a graph having color. . The user refers to the graph as an auxiliary means for focus adjustment.

As described above, according to the projection display apparatus 1200 according to the second embodiment, it is possible to provide auxiliary means when the user performs a manual focus adjustment operation. Since the current focus state is displayed as a color graph, the user can intuitively understand the focus state.

In the above description, the focus state determination unit tracks the change amount of the focus evaluation value, and calculates the focus evaluation value when the change amount changes from increase to decrease as the target value that the focus evaluation value should take. As described above, the target value to be taken as the focus evaluation value may be calculated by acquiring an input signal of an image projected on the screen 300 and analyzing the image. This can be realized by the focus evaluation value calculation unit 142 acquiring an input signal from the image memory 84 via the video signal setting unit 82, and directly analyzing the acquired input signal to calculate a target value.

When tracking the change amount of the focus evaluation value and calculating the focus evaluation value when the change amount changes from increasing to decreasing as the target value to be taken by the focus evaluation value, the maximum value is obtained until the change amount changes from increasing to decreasing. May not be determined, and only a provisional maximum value may be calculated. It is sufficient to detect when the amount of change in the focus evaluation value changes from increase to decrease as the maximum value. In this case, however, the focus must be out of focus once the focus is in the correct state, and focus adjustment is efficient. Can be impossible. These can be avoided by setting the target value to be taken as the focus evaluation value by acquiring the input signal of the image projected on the screen 300 and analyzing the image, and acquire the captured image captured by the imaging unit 30. As compared with the case of image analysis, it is advantageous in that a target value with higher accuracy can be set.

In the above description, it has been described that the focus state determination unit 154 tracks the amount of change in the focus evaluation value. However, the focus state determination unit 154 has changed the calculated amount of change in the focus evaluation value beyond a predetermined threshold. In this case, the focus evaluation value exceeding the threshold may be discarded from the focus evaluation value storage unit 152. Here, the predetermined threshold is a reference value for the change amount of the focus evaluation value for checking the reliability as the focus evaluation value. For example, when a situation occurs such as a hand in front of the camera or a person passing in front of the camera during focus assist, a correct focus evaluation value cannot be calculated, and the amount of change in the focus evaluation value increases. As a result, a malfunction may occur. Therefore, those situations are reproduced in advance by experiments, and a predetermined threshold is set. This is advantageous in that the above malfunction can be prevented.

In the above description, the case of a rectangle whose longitudinal direction is the horizontal direction with respect to the image projected on the screen as the graph representing the focus state information has been described, but the shape of the graph is not limited to a rectangle. For example, it may be a polygon such as a circle or a triangle. When the graph is a circle, it can be realized as a pie graph in which the focus evaluation value and the angle are associated with each other. Similarly, in the case of a polygon such as a triangle, it can be realized by associating the focus evaluation value with the area for filling the graph.

In the above description, a case has been described in which the zoom operation detection unit 144 determines whether or not the zoom operation is performed by acquiring the vertical stripe pattern imaged by the imaging unit 30 and analyzing the image. Various modes can be considered for the image to be subjected to the above. This aspect will be described below.

FIG. 14 is a diagram showing an example of a pattern image used for image analysis. FIG. 14A is a diagram showing a pattern image mainly used for focus adjustment. The checkered pattern as shown in FIG. 14 (a) contains many high-frequency components because edge components appear periodically, which is convenient for calculating the focus evaluation value. The zoom operation detection unit 144 can detect the zoom operation by analyzing the image of the checkerboard pattern. For example, when calculating a horizontal profile for a pattern and calculating its edge component, it is the same as using the vertical stripe pattern described above, but a profile in any direction can be used. is there. This is advantageous in that the calculation of the focus evaluation value and the determination of the presence or absence of the zoom operation can be performed simultaneously.

FIG. 14B is a diagram illustrating an example of a combination of a pattern image used for focus adjustment and a pattern image used for zoom operation detection. Specifically, the periphery of the checkered pattern image used for calculation of the focus evaluation value is an image surrounded by the vertical stripe pattern image used for determining the zoom operation. In this way, the image for use in calculating the focus evaluation value and the image for use in determining the zoom operation are spatially divided and arranged, so that the calculation of the focus evaluation value and the presence / absence of the zoom operation are determined. This is advantageous in that the determination can be executed simultaneously.

Alternatively, a checkered pattern image used to calculate the focus evaluation value and a vertical stripe pattern image used to determine the zoom operation may be alternately projected and displayed in a time-division manner. Since the image switching cycle needs to be slow enough not to give a visual discomfort to the user and fast enough not to interfere with calculation of the focus evaluation value and determination of the zoom operation, it is determined experimentally. For example, the cycle is 1 second. Since the focus evaluation value calculation unit 142 and the zoom operation detection unit 144 can analyze an image suitable for each operation, it is advantageous in that accuracy of calculation of the focus evaluation value and determination of the presence / absence of the zoom operation can be improved. It is.

The zoom operation detection unit 144 may detect the presence or absence of the zoom operation by acquiring and analyzing the graph representing the focus state information shown in FIG. As shown in FIG. 10, the graph representing the focus state information has a memory in the vertical direction. The zoom operation detection unit 144 can detect the presence or absence of the zoom operation by acquiring the interval of the memory and examining the fluctuation. There is no need to project a tasteless dry image for detecting the presence or absence of a zoom operation, which is advantageous in that the user's boredom felt during focus adjustment can be reduced.

When an image including a human face is projected on the screen 300, the zoom operation detection unit 144 can detect the presence or absence of the zoom operation by detecting the human face and examining the variation in the size thereof. it can. This can be realized by using a general image recognition technique such as pattern matching or color analysis. Alternatively, when a character is projected on the screen 300, the zoom operation detection unit 144 can detect the presence of the zoom operation by detecting the character and examining the change in its size. This can be realized, for example, using a general-purpose character recognition technique.

Third embodiment.
In autofocus adjustment using captured images, a method of adjusting the focus (contrast detection method) by calculating the contrast of images captured at a plurality of lens positions and detecting the lens position where the contrast is maximized. Often used.

オート In projector autofocus adjustment, it is necessary to focus on the screen surface. However, when the screen is not directly facing the projector, that is, when the screen is inclined, the distance between each position in the screen surface and the projector becomes non-uniform. In this case, the focus is adjusted to an area that is close to the projector on the screen surface, and an image in an area that is far from the projector may be out of focus. Further, when the screen is greatly inclined, even the image of the central area in the screen surface may be out of focus.

In the third embodiment of the present invention, it is an object to provide a technique for focusing on a suitable position in the screen surface even when the screen is inclined by autofocus adjustment using a contrast detection method. .

FIG. 15 is a diagram showing the positional relationship between the projection display apparatus 2200 and the screen 300 according to the third embodiment of the present invention. A projection display apparatus 2200 according to the third embodiment includes an imaging unit 30 for photographing the direction of the screen 300. The imaging unit 30 is installed so that the optical axis center thereof is parallel to the optical axis center of the projection light projected from the projection display apparatus 2200. In FIG. 15, the screen 300 does not face the projection display apparatus 2200 and the right side is inclined toward the heel.

FIG. 16 illustrates an example of a captured image PuI captured by the imaging unit 30 in the positional relationship illustrated in FIG. In the captured image PuI, a projection image PrI projected from the projection display apparatus 2200 on which a test pattern is drawn is shown. Further, the image SI of the screen 300 is also captured in the captured image PuI. Since the amount of light projected at each position in the screen 300 is inversely proportional to the square of the distance from the light source, the luminance level gradually decreases from the left side to the right side of the image SI on the screen 300. Hereinafter, autofocus processing for focusing on a suitable position within the screen 300 will be described.

FIG. 17 is a diagram showing a configuration of a projection display apparatus 2200 according to the third embodiment. The projection display apparatus 200 includes a projection unit 10, a lens driving unit 20, an imaging unit 30, and a control device 2100. The control device 2100 includes a screen position detection unit 240, a detection area setting unit 250, an autofocus adjustment unit 260, a video signal setting unit 82, an image memory 84, and a drive signal setting unit 86.

The configuration of the control device 2100 can be realized in terms of hardware by a CPU, memory, or other LSI of an arbitrary computer, and in terms of software, it can be realized by a program loaded in the memory. Depicts functional blocks realized by. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

The light modulator 12 modulates the light incident from the light source 11 in accordance with the video signal set by the video signal setting unit 82. For example, a DMD (Digital Micromirror Device) can be employed for the light modulator 12. The DMD includes a plurality of micromirrors corresponding to the number of pixels, and generates desired video light by controlling the direction of each micromirror according to each pixel signal.

The focus lens 13 adjusts the focal position of the light incident from the light modulator 12. The lens position of the focus lens 13 is moved on the optical axis by the lens driving unit 20. The image light generated by the light modulation unit 12 is projected onto the screen 300 via the focus lens 13.

The lens driving unit 20 moves the position of the focus lens 13 in accordance with the driving signal set from the driving signal setting unit 86. For the lens driving unit 20, a stepping motor, a voice coil motor (VCM), a piezoelectric element, or the like can be employed.

The imaging unit 30 captures the screen 300 and the projected image projected on the screen 300 as a main subject. The imaging unit 30 includes a solid-state imaging device 31 and a signal processing circuit 32. As the solid-state imaging device 31, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, a CCD (Charge Coupled Devices) image sensor, or the like can be employed. The signal processing circuit 32 performs various signal processing such as A / D conversion and conversion from the RGB format to the YUV format on the signal output from the solid-state imaging device 31, and outputs the signal to the control device 2100. In this embodiment, the data is output to the screen position detection unit 240 and the detection area setting unit 250.

The screen position detection unit 240 detects the position of the screen shown in the image picked up by the image pickup unit 30. More specifically, the screen position detection unit 240 detects the positions of the four sides (upper side, lower side, left side, and right side) of the screen 300 captured in the captured image by extracting edges in the captured image. The detected screen position is set in the detection area setting unit 250. The screen position is specified by, for example, vertex coordinates of four corners.

The detection area setting unit 250 sets a central area in the screen area detected by the screen position detection unit 240 as a detection area.

FIG. 18 is a diagram illustrating a state in which the detection area DA is set in the screen area SA in the captured image PuI according to the third embodiment. FIG. 19 is a diagram for explaining an example of a detection area DA setting method according to the third embodiment. As shown in FIG. 18, the detection area setting unit 250 acquires the position of the screen area SA from the screen position detection unit 240, and sets the center area as the detection area DA. The position and size of the detection area DA are determined as follows, for example.

As shown in FIG. 19, the detection area setting unit 250 sets the maximum rectangle IR inscribed in the screen area SA. Next, the rectangle IR is divided into three equal parts in the vertical direction and the horizontal direction. The middle rectangle among the nine rectangles thus formed is set in the detection area DA.

FIG. 19 illustrates an example in which horizontal trapezoidal distortion is generated in the screen area SA due to the screen 300 tilting in the left-right direction. The detection area DA can be set by the above algorithm even when trapezoidal distortion occurs or when both horizontal and vertical trapezoidal distortions occur. In this algorithm, the detection area DA can be set by simple calculation regardless of the position and size of the screen area SA.

Note that the size of the detection area DA set in the center area of the screen area SA is not limited to the size calculated by the above algorithm. The size of the detection area DA may be set to a value derived by the designer based on experiments and simulations. The value may be a value when the detection accuracy of a trapezoidal distortion detection test pattern and / or the evaluation value of the subjective image quality, which will be described later, is maximized in experiments and simulations. Note that the size of the detection area DA that is actually set is a normalized value according to the size of the screen area SA.

Also, the size of the detection area DA may be adjusted according to the specifications (for example, S / N ratio, resolution) of the camera mounted on the projection display apparatus 2200. For example, when the S / N ratio is low, the influence of noise increases, so that the size of the detection area DA needs to be relatively large in order to maintain the autofocus adjustment accuracy. On the other hand, since the influence of noise is small when the S / N ratio is high, the autofocus adjustment accuracy is maintained even if the size of the detection area DA is reduced. Similarly, when the resolution is low, the size of the detection area DA needs to be relatively large. The designer may perform the experiment and simulation for each camera having different specifications.

Return to FIG. The autofocus adjustment unit 260 adjusts the focus using a contrast detection method. When the projection display apparatus 2200 is activated or when auto focus adjustment is instructed by a user operation, the video signal setting unit 82 reads out a test pattern for auto focus adjustment from the image memory 84 and causes the projection unit 10 to project the test pattern. . The test pattern is formed of, for example, a stripe pattern or a checker flag pattern. The imaging unit 30 images the test pattern projected on the screen 300.

The autofocus adjustment unit 260 is configured to determine the position of the lens based on the sharpness of the detection area set by the screen position detection unit 240 in a plurality of images respectively captured by the imaging unit 30 at a plurality of lens positions. To decide. Hereinafter, the configuration of the autofocus adjustment unit 260 will be described more specifically.

The autofocus adjustment unit 260 includes a high-pass filter 261, an integration unit 262, and a lens position determination unit 263. The high pass filter 261 extracts a high frequency component exceeding a predetermined threshold value of the image signal in the detection region, and supplies the extracted high frequency component to the integrating unit 262. The high pass filter 261 may extract high frequency components in the horizontal direction, or may extract high frequency components in both the horizontal direction and the vertical direction.

The integrating unit 262 integrates the high frequency components extracted by the high pass filter 261 at each lens position, and supplies the integrated high frequency component to the lens position determining unit 263. When high frequency components are extracted in both the horizontal direction and the vertical direction by the high-pass filter 261, the integrating unit 62 adds both high frequency components. The lens position determining unit 263 determines the position of the focus lens 13 from which the maximum integrated value is detected among the plurality of integrated values supplied from the integrating unit 262 as the in-focus position.

FIG. 20 is a diagram for explaining the process of determining the focus position of the focus lens 13. When the autofocus function is enabled, the autofocus adjustment unit 260 instructs the video signal setting unit 82 to project a test pattern, and moves the focus lens 13 from the near side to the far side or from the far side to the near side. A control signal for sequentially moving in a predetermined step width is set in the drive signal setting unit 86. The video signal setting unit 82 sets the video signal of the test pattern in the light modulation unit 12, and the drive signal setting unit 86 sets the drive signal corresponding to the control signal in the lens driving unit 20.

The autofocus adjustment unit 260 calculates the sharpness (the above integrated value can be used) included in the test pattern imaged at each lens position of the focus lens 13. This sharpness increases as the focus lens 13 approaches the in-focus position. When the increase peaks and decreases, the autofocus adjustment unit 260 determines the previous lens position as the in-focus position.

Return to FIG. The image memory 84 holds image data to be projected on the screen 300. The image data is supplied from a PC or the like via an external interface (not shown). In the present embodiment, a test pattern projected during autofocus adjustment is also held. The video signal setting unit 82 sets a video signal based on the image data held in the image memory 84 in the light modulation unit 12. The drive signal setting unit 86 sets a drive signal for moving the focus lens 13 to the lens position instructed from the autofocus adjustment unit 260 in the lens drive unit 20.

As described above, according to the third embodiment, by setting the detection area in the central area of the screen, even when the screen is tilted, it is suitable for the position on the screen surface, that is, in the central area of the screen. Focus can be adjusted. In addition, the amount of calculation can be reduced by detecting the sharpness of each image using the image signal of the detection area instead of the image signal of the entire captured image. Therefore, the autofocus adjustment time can be shortened.

Fourth embodiment.
FIG. 21 is a diagram showing a configuration of a projection display apparatus 3200 according to the fourth embodiment of the present invention. The projection display apparatus 3200 according to the fourth embodiment has a configuration in which a side length measurement unit 245 is added to the projection display apparatus 2200 according to the third embodiment.

The side length measurement unit 245 measures the lengths of the two opposite sides of the screen area detected by the screen position detection unit 240. The side length measurement unit 245 can detect the inclination of the screen 300 from the lengths of these two sides. More specifically, the lengths of the left and right sides of the screen area are measured, and the horizontal tilt of the screen 300 is detected. Note that the ratio of the lengths of the left side and the right side may be calculated to detect the degree of inclination. It shows that the inclination is so large that the said ratio is large. Similarly, the lengths of the upper and lower sides of the screen area are measured, and the vertical tilt of the screen 300 is detected.

The detection area setting unit 250 moves the detection area set as the central area of the screen area by a predetermined distance in the direction of the short side of the two sides measured by the side length measurement unit 245.

FIG. 22 is a diagram illustrating a state in which the detection area DA is set in the screen area SA in the captured image PuI according to the fourth embodiment. The detection area DA shown in FIG. 22 is moved in the right direction with respect to the detection area DA shown in FIG. Since the length of the right side of the screen area SA is shorter than the length of the left side, the detection area setting unit 250 moves the detection area DA from the central area to the right side. In FIG. 22, since the example in which the length of the upper side and the length of the lower side of the screen area SA are equal is drawn, the detection area DA is not moved in the vertical direction. Moved.

The distance by which the detection area DA is moved from the central area in the direction of the short side may be set to a value derived by the designer based on experiments and simulations. This value may be a value when the detection accuracy and / or subjective image quality evaluation value of the trapezoidal distortion detection test pattern, which will be described later, is maximized in the experiment or simulation. As described above, the distance may be adjusted according to the specifications (for example, S / N ratio, resolution) of the camera mounted on the projection display apparatus 3200. Note that the distance actually moved in the direction of the short side is a normalized value according to the size of the screen area.

Further, the detection area setting unit 250 may adaptively change the distance for moving the detection area DA according to the degree of inclination of the screen 300 detected by the side length measurement unit 245. For example, the detection area setting unit 250 increases the distance by which the detection area DA is moved as the inclination increases.

As described above, according to the fourth embodiment, even if the screen is tilted by setting the detection region at a position slightly shifted from the central region of the screen in a direction far from the light source, the screen The focus can be adjusted to a suitable position in the plane.

In the inventor's experiment, the trapezoidal distortion described later is more effective when the detection area is set at a position slightly shifted in the direction far from the light source from the central area of the screen than when the detection area is set in the central area of the screen. The result that the detection accuracy of the test pattern for detection was high was obtained. Moreover, the result that a big difference did not arise in the evaluation value of subjective image quality was obtained. Thus, the method of focusing on a position shifted in a direction farther from the light source than the central region of the screen is an effective method.

In the fourth embodiment, it has been described that the detection area is set at a position slightly shifted from the center area of the screen in a direction far from the light source, but the detection area may be set at another position. For example, as shown in FIG. 23, when each side of the screen area is equally divided into nine areas, the detection area DA may be moved to an area including any corner of the screen area SA. Good. In FIG. 23, the detection area DA is moved to the corner where the shorter side intersects when the opposite sides are compared in the screen area SA. The reason why the detection area DA is moved in the direction of the short side is that if the detection area is set closer to the long side, the luminance change in the detection area becomes larger than that set near the short side. This is because the in-focus position of the focus lens 13 is closer to the longer side, and this must be avoided.

Note that the destination of the detection area may be set to an optimal position based on the position of the projection display apparatus, the distance between the projection display apparatus and the screen, and the like.

In the third and fourth embodiments, the autofocus adjustment unit 260 may cause the projection unit 10 to project a test pattern for autofocus adjustment in the central detection region or the detection region after movement. In this case, focus information for assisting the user in adjusting the focus may be projected on the projection unit 10 in a screen area other than the detection area. The focus information includes a focus adjustment bar, button, focus evaluation value, character information, and the like. The user can finely adjust the focus by operating the bar or button with the mouse or the laser pointer while referring to the focus evaluation value or the like.

Fifth embodiment.
FIG. 24 is a diagram showing a configuration of a projection display apparatus 4200 according to the fifth embodiment of the present invention. The projection display apparatus 4200 according to the fifth embodiment has a configuration in which a trapezoidal distortion correction unit 270 is added to the projection display apparatus 2200 according to the third embodiment.

The trapezoidal distortion correction unit 270 detects the distortion in the shape of the test pattern for detecting the trapezoidal distortion by detecting an edge in the image captured by the imaging unit 30, and corrects the video signal so that the distortion is canceled. To do. The trapezoidal distortion occurs when the screen 300 and the projection display apparatus 4200 are not facing each other. For example, when the optical axis of the projection light is shifted upward, a trapezoidal distortion in which the upper portion of the screen 300 swells occurs.

When keystone distortion adjustment is instructed when the projection display apparatus 4200 is activated or when a user operation is instructed, the video signal setting unit 82 reads a test pattern for keystone distortion adjustment from the image memory 84 and projects it onto the projection unit 10. Let The test pattern is formed of, for example, a quadrangle (square, rectangle, parallelogram, rhombus, etc.). The imaging unit 30 images the test pattern projected on the screen 300. The trapezoidal distortion correction unit 270 detects the trapezoidal distortion based on the shape of the test pattern reflected in the captured image, and corrects the video signal to be set in the video signal setting unit 82 so that the trapezoidal distortion is canceled. . The video signal setting unit 82 sets the video signal after the trapezoidal distortion correction supplied from the trapezoidal distortion correction unit 270 to the light modulation unit 12 during a period in which the trapezoidal distortion correction function by the trapezoidal distortion correction unit 270 is valid.

When starting up the projection display apparatus 4200, the trapezoidal distortion correction unit 270 performs the trapezoidal distortion detection process described above after the focus adjustment by the autofocus adjustment unit 260 is completed. Hereinafter, the configuration of the trapezoidal distortion correction unit 270 will be described more specifically.

The trapezoidal distortion correction unit 270 includes an edge extraction unit 271, a distortion detection unit 272, and a video signal correction unit 273. The edge extraction unit 271 detects an edge from the captured image in which the test pattern is captured. At this time, the edge extraction unit 271 extracts an edge within the screen area set by the screen position detection unit 240. The edge is extracted at a location where a luminance level change exceeding a predetermined threshold has occurred.

The distortion detection unit 272 specifies how much it swells in the vertical and horizontal directions from the vertex coordinates of the test pattern specified by edge extraction. The video signal correction unit 273 corrects the video signal to be set in the video signal setting unit 82 so that the swelling of the test pattern projected on the screen 300 is cancelled.

FIG. 25 is a diagram for explaining trapezoidal distortion correction. FIG. 25A shows vertical trapezoidal distortion correction, and FIG. 25B shows horizontal trapezoidal distortion correction. In FIG. 25A, the upper part of the projection image PrI is swollen. The video signal correction unit 273 gradually scales down the horizontal width of the video from the upper end to the lower end of the video to be projected so that a quadrangle whose aspect ratio is maintained is projected onto the screen 300. In FIG. 25B, the left part of the projection image PrI is swollen. The video signal correction unit 732 gradually scales down the vertical width of the video from the left end to the right end of the video to be projected so that a quadrangle whose aspect ratio is maintained is projected onto the screen 300.

FIG. 26 is a diagram illustrating a state in which a trapezoidal distortion detection test pattern TP is reflected in the screen area SA in the captured image PuI according to the fifth embodiment. This captured image PuI is focused on the left area of the screen area SA. That is, a case is shown in which the autofocus adjustment is performed using the image signal of the entire captured image or the entire screen area SA without setting the detection area described in the third and fourth embodiments. In this case, the focus is focused on the left area of the screen area SA that is closer to the light source than the center area of the screen area SA.

Thereafter, when a test pattern TP for trapezoidal distortion detection is projected onto the screen 300 and captured by the imaging unit 30, the left part of the test pattern TP is clearly visible in the captured image PuI as shown in FIG. The right part is out of focus (in FIG. 26, the out of focus is indicated by a dotted line). In this case, the edge extraction unit 271 may not be able to extract a part of the shape of the test pattern TP from the captured image PuI. If it cannot be extracted, the accuracy of the trapezoidal distortion correction is reduced.

On the other hand, when the detection area described in the third and fourth embodiments is set and the auto focus adjustment is performed using the image signal of the detection area, the center area of the screen area SA or a little from there. The focus is adjusted to the position shifted to the right. Thereafter, when a test pattern for trapezoidal distortion detection is projected onto the screen 300 and captured by the imaging unit 30, the entire test pattern appears in the captured image without being out of focus. Therefore, the edge extraction unit 271 can extract the shape of the entire test pattern from the captured image, and the accuracy of trapezoidal distortion correction is improved.

As described above, according to the fifth embodiment, after the autofocus adjustment described in the third and fourth embodiments is performed, trapezoidal distortion detection is performed, thereby improving the accuracy of trapezoidal distortion correction. Can do. On the other hand, if the trapezoidal distortion detection is executed before the autofocus adjustment or after the autofocus adjustment using the image signal of the entire captured image or the entire screen area, the accuracy of the trapezoidal distortion correction may be lowered. This is because the shape of the entire test pattern may not be extracted from the captured image.

The present invention has been described based on the embodiments. It is understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. By the way.

In the fourth embodiment, the detection area setting unit 250 may adaptively change the size of the detection area according to the degree of inclination of the screen 300 detected by the side length measurement unit 245. For example, the detection area setting unit 250 reduces the size of the detection area as the inclination increases. If the inclination is large, the detection area is focused on the side closer to the light source than the center. Therefore, the smaller the size of the detection area, the closer the focus can be to the center of the entire screen area.

In the fifth embodiment, a shape correction unit may be provided instead of the trapezoidal distortion correction unit 270. The shape correction unit executes shape correction such as well-known four-point correction (fitting correction). The video signal setting unit 82 causes the projection unit 10 to project a test pattern for four-point correction, such as when the projection display apparatus is activated. The test pattern is, for example, a white rectangle. The imaging unit 30 images the test pattern projected on the screen 300. After the focus adjustment by the autofocus adjustment unit 260 is completed, the shape correction unit sets the video to be set in the video signal setting unit 82 so that the four vertices of the test pattern shown in the captured image coincide with the four vertices of the screen. Correct the signal. The video signal setting unit 82 sets the corrected video signal supplied from the shape correction unit in the light modulation unit 12.

FIG. 27 is a diagram for explaining the four-point correction. FIG. 27 is a captured image, and shows a state where a projected image (for example, a white test pattern) PrI is projected out of the screen 300. As indicated by arrows in the figure, the shape of the video is adjusted so that the four vertices of the projection image PrI coincide with the corresponding four vertices of the screen 300.

Note that the shape correction unit may select and execute either trapezoidal distortion correction or four-point correction based on the shape characteristics of the projection image PrI.

DESCRIPTION OF SYMBOLS 10 Projection part, 11 Light source, 12 Light modulation part, 13 Focus lens, 20 Lens drive part, 30 Imaging part, 40 Focus evaluation part, 42 Focus evaluation value calculation part, 44 Evaluation value change detection part, 50 Video signal evaluation part, 52 input signal evaluation value calculation unit, 54 input signal evaluation value determination unit, 60 focus target calculation unit, 70 focus adjustment assist unit, 82 video signal setting unit, 100, 1100, 2100, 3100, 4100 control unit, 144 zoom operation detection , 150 focus state information setting unit, 152 focus evaluation value storage unit, 154 focus state determination unit, 156 graph database, 200, 1200, 2200, 3200, 4200 projection type video display device, 240 screen position detection unit, 245 side length Measurement unit, 250 detection area setting unit 260 auto-focus adjustment unit, 261 high-pass filter, 262 integration unit, 263 a lens position determining section 270 distortion corrector, 271 edge extraction unit, 272 distortion detector, 273 image signal modifier 300 screen.

Claims

Mounted in a projection display apparatus that includes a projection unit that projects an image on a screen via a lens, an imaging unit for imaging the screen, and a focus adjustment unit that is provided in the projection unit and is manually operated. A control device,
A focus evaluation value calculation unit that acquires a captured image captured by the imaging unit and calculates a characteristic value that changes according to a focus state of an image projected on a screen as a focus evaluation value;
An evaluation value change detection unit for determining that the focus adjustment unit is operated by a user when the focus evaluation value is changed;
A focus adjustment assisting unit that projects and displays focus in-focus information for assisting focus adjustment together with the video when it is determined that the focus adjustment unit is operated;
A control device comprising:
The evaluation value calculation unit divides the captured image into a plurality of regions, calculates the focus evaluation value for each region,
The control according to claim 1, wherein the evaluation value change detection unit determines that the focus adjustment unit is operated by a user according to the number of regions in which the focus evaluation value changes. apparatus.
The evaluation value change detection unit determines that the operation of the focus adjustment unit by the user has ended when the focus evaluation value no longer changes,
The control apparatus according to claim 1, wherein the focus adjustment assist unit ends the projection display of the focus in-focus information.
An input signal evaluation value calculation unit that acquires a video signal projected on the screen and calculates a characteristic value that changes according to the presence or absence of motion in the video as an input signal evaluation value;
An input signal evaluation value determining unit that determines that the video is a still image when the input signal evaluation value does not change over a predetermined period;
4. The control device according to claim 1, wherein the focus adjustment assist unit projects and displays the focus focusing information when it is determined that the video is a still image.
A zoom operation detection unit that determines whether or not the user is operating the zoom adjustment unit by acquiring and analyzing a captured image captured by the imaging unit;
A focus state determination unit that derives focus state information by tracking a change in the focus evaluation value acquired from the focus evaluation value calculation unit, and
The focus state determination unit restarts tracking of a change in a focus evaluation value triggered by a determination that the zoom adjustment unit is operated by the zoom operation detection unit. Control device.
A video signal setting unit for setting the focus state information as an image to be projected and displayed together with the image;
The zoom operation detection unit determines that the zoom adjustment unit is operated by a user by acquiring an image of focus state information projected on the screen and analyzing the image. The control device described in 1.
An image signal setting unit that projects and displays, as the image, an image in which the periphery of the image used for calculating the focus evaluation value is surrounded by an image used for determining the zoom operation is further included. Item 6. The control device according to Item 5.
The video signal setting unit further includes a video signal setting unit configured to alternately project and display a video for use in calculating a focus evaluation value and a video for use in determining a zoom operation as the video in a time-division manner. 5. The control device according to 5.
A control device to be mounted on a projection display apparatus comprising: a projection unit that projects an image on a screen through a lens; and an imaging unit for imaging the screen,
A screen position detection unit for detecting a position of a screen captured in an image captured by the imaging unit;
A detection region setting unit that sets a central region in the screen region detected by the screen position detection unit as a detection region;
A focus adjustment unit that determines the position of the lens based on the sharpness of the detection area in a plurality of images respectively captured by the imaging unit at a plurality of lens positions;
A control device comprising:
10. The control device according to claim 9, wherein the detection area setting unit moves the set detection area within the screen area.
A side length measuring unit for measuring the lengths of two opposite sides of the screen area detected by the screen position detecting unit;
The control device according to claim 10, wherein the detection region setting unit moves the detection region by a predetermined distance in a direction of a short side of two sides measured by the side length measurement unit. .
The control apparatus according to claim 9, wherein the focus adjustment unit projects a test pattern for focus adjustment into the detection area via the projection unit.
13. The control apparatus according to claim 12, wherein the focus adjustment unit projects focus information for supporting focus adjustment by a user through the projection unit in a screen area other than the detection area.
Further comprising a shape correction unit that detects distortion in the shape of the test pattern by detecting an edge in the image captured by the imaging unit, and corrects the video signal so that the distortion is canceled;
The control device according to claim 9, wherein the shape correction unit executes a shape distortion detection process after the focus adjustment by the focus adjustment unit is completed.
A projection unit that projects an image onto a screen via a lens;
An imaging unit for imaging the screen;
A control device according to any one of claims 1 to 14,
A projection-type image display device comprising: