JP2004088169A - Image display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display which accurately and quickly corrects the distortion of an image projected on a screen. <P>SOLUTION: The display comprises a means for projecting a projective image on a projecting plane, a two-dimensional PSD for receiving reflected lights from a plurality of light points on the image projected on the projecting plane, a position detector circuit for detecting the positions of the plurality of light points, and a control means for detecting and correcting the distortion of the image projected on the projecting plane by the image projecting means, based on the positions of the plurality of light points detected by the position detector circuit. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image display device (projector) that projects characters, graphics, and the like transmitted from a personal computer, a video device, or the like on a screen, and more particularly, an image projection angle of the image display device with respect to a screen surface (projection surface). The present invention relates to an image display device that corrects a distortion of a projection image generated when the image is not vertical.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an image display device that enlarges and projects an image on a screen is known.
This image display device is roughly classified into a front type and a rear type. The front type is a type that projects an image toward a screen installed in front of the image display device like a movie. The rear type has a built-in transmissive screen inside the image display device main body, and the back side of this screen Is a type of projecting an image from.
[0003]
In the front type image display device, since the image display device main body and the projection surface such as a screen are formed separately, large-screen display is possible, but it is necessary to increase the projection distance in proportion to the screen size. There is. However, when the image projection device is not arranged so that the image projection angle is perpendicular to the screen surface (projection surface) (for example, from the lower position of the screen to the vertical In the case of an arrangement relationship in which projection is performed toward the image display device itself, the projected image may be distorted into a trapezoidal shape or a quadrilateral shape as the arrangement distance of the screen becomes longer. Become.
[0004]
Conventional means for correcting this distortion include a manual operation of an adjusting device of an image display device main body while an operator performs a process while viewing a projected image on a screen, and a method disclosed in, for example, JP-A-8-9309. As described above, it has been known to automatically detect the amount of distortion from projection light emitted from the projection surface of the image display device and reflected light from the projection surface to perform distortion correction. In the present apparatus, distortion that may be caused by measuring the distance between the main unit and a plurality of points on the screen by a distance sensor using an ultrasonic method or an LED or a laser diode is corrected (Example 1). Alternatively, a test pattern image having a plurality of predetermined light spots is projected, and a CCD camera installed in the image display device detects the position of each light spot, thereby distorting the image on the projection surface (screen surface). Was detected (Example 2).
[0005]
[Problems to be solved by the invention]
However, such a distortion detection method using a distance sensor or a CCD camera requires complicated processing in hardware and software and requires a large amount of processing time, so that the processing speed of the entire distortion correction processing is slow. There was a problem.
[0006]
When a CCD camera is used as the detecting means, when the light spots on the test pattern captured from the projection plane are out of focus and the outline of the light spots is blurred, the position of each light spot is changed. Since accurate detection cannot be performed, distortion of the image on the projection surface cannot be detected accurately, resulting in a problem that accurate distortion correction cannot be performed.
[0007]
The present invention has been made in view of the related art as described above, and has as its object to provide an image display device capable of accurately and quickly correcting distortion of an image projected on a projection surface. And
[0008]
[Means for Solving the Problems]
For this reason, the present invention provides a projection unit that projects a projection image toward a projection surface, a two-dimensional PSD that receives reflected light from a plurality of light points in the projection image projected on the projection surface, A position detection circuit that detects the positions of the plurality of light spots in the projection image based on an output signal from a PSD, and the image projection unit based on the positions of the plurality of light spots detected by the position detection circuit And control means for detecting distortion of the projected image projected on the projection surface and correcting the distortion.
[0009]
Here, the image display device of the present invention is provided with a two-dimensional PSD that receives reflected light from a plurality of light points in the projected image projected on the projection surface, so that the projected image projected on the projection surface is provided. And the distortion can be detected accurately and efficiently.
[0010]
Further, the present invention provides a projection unit for projecting a projection image toward a projection surface, an inclination detection unit for detecting an inclination of a projection axis of the projection unit with respect to the projection surface, and a projection image projected on the projection surface. A PSD for receiving reflected light from a plurality of light spots, a position detection circuit for detecting the positions of the plurality of light spots in the projected image based on an output signal from the PSD, and the inclination detection means Based on the detection result, a distortion caused by a tilt in any one of a vertical direction and a horizontal direction of the projection image projected on the projection surface is detected, the distortion is corrected, and the plurality of lights detected by the PSD are detected. The present invention provides an image display apparatus comprising: a control unit configured to detect a distortion in the other direction of a projected image projected on the projection plane based on a position of a point and to correct the distortion.
[0011]
Here, the provision of the PDS and the inclination detecting means makes it possible to correct the distortion and the inclination of the projected image projected on the projection surface accurately and in a short time.
[0012]
The inclination detecting means is a gyroscope, and is configured to detect the inclination of the projection axis of the projection means with respect to the projection plane by detecting the inclination of the apparatus main body with respect to the support means for supporting the apparatus main body.
[0013]
Further, the PSD can be realized by a one-dimensional PSD or a two-dimensional PSD.
[0014]
Further, the present invention provides a projection unit for projecting a projection image toward a projection surface, two PSDs for receiving light reflected from a plurality of light points in the projection image projected on the projection surface, and the two PSDs. A position detecting circuit for detecting positions in the plurality of vertical directions in the projected image based on an output signal from one of the PSDs, and detecting positions in the horizontal direction of the plurality of light spots based on the output of the other PSD And control means for detecting and correcting distortion of a projection image projected on the projection surface by the image projection means based on positions of the plurality of light spots detected by the position detection circuit. To provide an image display device.
[0015]
Each of the two PSDs is a one-dimensional PSD.
[0016]
Here, by providing the two PSDs in the image display device, there is no interference between the electrodes that can occur in the two-dimensional PSD, and the distortion and inclination of the projected image projected on the projection surface can be accurately and quickly measured. It became possible to correct.
[0017]
Here, the control unit is configured to detect and correct the distortion of the projection image at predetermined time intervals. Thereby, even if the projection image or the image display device itself changes with the elapse of time, a distortion occurs in the projection image, the projection image is automatically corrected and a projection image without distortion can be provided.
[0018]
Furthermore, the PSD includes at least one pair of electrodes, photoelectric conversion means for receiving a spot-like light from the light spot and generating a current supplied to the at least one pair of electrodes, and the PSD between the at least one pair of electrodes. And a resistor that conducts current.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of an image display device according to the present invention will be described in detail with reference to the drawings.
[0020]
The image display device is an image projector (hereinafter, referred to as “projector”) used by connecting to a personal computer or the like. The projector 11 includes a liquid crystal system using a liquid crystal panel and a digital light processing (DLP) system using a DMD (digital micromirror device). The following embodiment is a projector based on the latter DLP system. Although the eleventh example will be described, it goes without saying that the present invention is applied to a liquid crystal projector as it is.
[0021]
FIG. 1 shows a configuration of an embodiment of a projector 11 adopting the DLP method. The projector 11 includes an image signal input unit 12, an image processing unit 13, an image projection unit 14, an image input unit (15a, 15b), an automatic focus adjustment unit 16, an automatic distortion correction control unit 17, and tilt detection as required. The image projection unit 14 includes a light source (lamp unit 24) and the like. In addition to the projector 11, a projection surface (screen 20) for displaying an image projected by the image projection means 14 is provided outside.
[0022]
The image signal input means 12 realizes input of an image signal, and includes an interface unit for receiving an image signal from an external device 12a such as a personal computer or a video device or an image memory 12b built in the projector 11. In this interface section, digital signals such as texts and charts created by a personal computer are directly transferred to the image processing means 13, and video output signals, Y / C output signals or RGB output signals output from video equipment or the like are output. With such an analog signal, the analog signal is subjected to A / D conversion processing and transferred to the image processing means 13.
[0023]
The image signal captured by the image signal input unit 12 includes test images used in an automatic focus adjustment unit 16, an automatic distortion correction control unit 17, and a tilt detection unit 18 in addition to original characters and figures.
[0024]
In this test image, as shown in FIG. 2, patterns 1 to 6 are prepared in which the central portion and the four corners emit white light in a point-like manner. The pattern 1 is used when the light receiving element mounted on the light receiving unit 41 of the image input unit 15a described later is a CCD, and the patterns 2 to 6 are used when the PSD is a PSD.
[0025]
As shown in FIG. 3, the image processing means 13 includes a digital processor (CPU), a digital format part, a digital display part, and a DMD driving part. The image signal input means 12, an automatic distortion correction control means described later Various digital signal processing is performed on the image signal that has passed through 17 and the inclination detecting means 18.
[0026]
Well-known image processing techniques are used for the processing content according to the type of image to be displayed. However, if the main ones are shown, scaling to change the size of the image to an appropriate size, synthesis of a plurality of images And color conversion to be added to an image, error diffusion, gamma correction, and the like. The image data processed in this way is sequentially stored in the frame memory. Then, the image data stored in the frame memory is taken out by the memory control unit, and is projected as a light image by the lamp unit 24 and the image projection unit 14 described later.
[0027]
The image projection means 14 has a mechanism for projecting the image image converted by the image processing means 13 onto the screen 20 at a predetermined distance from the projection lens 40 by the light emitted from the lamp unit 24. FIGS. 4 and 5 show the structure of the image projecting means 14, in which the color wheel 35, the integrator 36, the condenser lens 37, and the DMD 38 (digital micro mirror Device), a mirror 39, and a projection lens 40 in this order.
[0028]
The lamp unit 24 includes a lamp 31 that emits white light, and a semicircular reflector 32 surrounding the rear surface of the lamp 31. Further, a cooling fan 33 is provided to cool the heat generated when the lamp 31 emits light. The color wheel 35 is a single disk-shaped filter in which three color regions of RGB (red, green, blue) are formed, and transmits white light emitted from the lamp 31 while rotating at high speed. The transmitted light reaches the condenser lens 37 via the integrator 36.
[0029]
The light collected by the condenser lens 37 is reflected by the mirror 39 onto the surface of the DMD 38. The DMD 38 has been developed as a display device for a projector, and has a fingertip-sized silicon chip as a substrate on which a number of ultra-small aluminum movable mirrors are formed. The number of the movable mirrors is provided for the pixels of the image to be displayed, and the color tone and the like of the projected image are adjusted by reflected light due to slight inclination of each movable mirror.
[0030]
Next, in the projector 11 of the present invention, image input means (15a, 15b), automatic focus adjustment means 16, and automatic distortion correction control means 17, which are main means for enabling accurate and quick correction of the distortion of the projected image. And the inclination detecting means 18 will be described in detail.
[0031]
FIG. 6 is a front perspective view of the projector 11. FIG. 6A shows the projector 11 on which the two-dimensional PSD 25a is mounted. A projection lens 40 and a light receiving unit 41 of the two-dimensional PSD 25a are provided at a predetermined position with respect to the projection lens 40. FIG. 6B shows the projector 11 equipped with two one-dimensional PSDs 25b (for detecting the vertical position and the horizontal position), and each PSD light receiving unit 41 is disposed at a predetermined position with respect to the projection lens 40. Have been. 6C, the light receiving unit 41 of the horizontal one-dimensional PSD 25b, the support unit 60, and the tilt detecting unit 18 in the projector 11 are provided at predetermined positions with respect to the projection lens 40.
[0032]
FIG. 1 shows two systems of the image input means (15a, 15b), but in an actual apparatus configuration, one image input apparatus is switched to the automatic focus adjustment means 16 and the automatic distortion correction control means 17. Reflected light or reflected image is adopted.
[0033]
As shown in FIG. 7, the image input means (15a, 15b) includes a light receiving section 41, a signal processing section 42, and an A / D conversion section 43. The light receiving section 41 includes a light receiving element formed of a PSD 25a, 25b (Position Sensitive Detector) or a CCD (Charge Coupled Device) for receiving the light reflected by the screen 20.
[0034]
The above-mentioned PSDs 25a and 25b are so-called position detecting elements, and an automatic focus adjusting unit 16 detects an incident position of light reflected by the screen 20 and prepares the image projecting unit 14 based on the incident position. The distance from the projected lens 40 to the screen 20 is calculated.
[0035]
The automatic distortion correction control means 17 described later detects the positions of the white light emitting points of the pattern 1 or the patterns 2 to 6 shown in FIG. 2 and converts them into coordinates for performing distortion correction. The PSDs 25a and 25b, which are the light receiving elements of the light emitting unit 41, sequentially take in the patterns 2 to 6 that are continuously projected from the image projection unit 14.
[0036]
In the image display device of the present invention, it is possible to detect the distortion of the projected image by using the two-dimensional PSD or two one-dimensional PSDs, but it is possible to detect any one of the vertical direction and the horizontal direction with respect to the screen 20 (projection plane). The inclination detecting means 18 can be used to detect the inclination.
[0037]
In this case, as an example of the inclination detecting means 18, a gyroscope 48a is used as shown in FIG. The gyroscope 48a detects the inclination of the projection axis of the main body of the projector 11 with respect to the screen 20 by detecting the inclination of the main body of the projector 11 with respect to the support means for supporting the main body of the projector 11.
[0038]
The tilt detecting means 18 processes the tilt signal of the projector 11 main body detected by the gyroscope 48a in the tilt correction processing section 48b, and the tilt correction processing section 48b sends the tilt correction signal to the tilt control means 49 to operate the support means 60. By doing so, the inclination of the light projecting axis is corrected so as to match the reference light projecting axis.
[0039]
Next, the PSD 25 used in the image display device according to the present invention will be described.
[0040]
FIG. 9 is a sectional view of the basic configuration of the PSD 25b (one-dimensional). FIG. 9A shows a plan view of the PSD 25b. FIG. 9B shows a cross-sectional view of the PSD 25b. The basic structure of the PSD 25b is such that a uniform resistance layer is formed on one or both sides of a high-resistance semiconductor substrate, and a pair of electrodes for signal extraction are provided at both ends of the resistance layer. The light receiving surface forms a PN junction at the same time as the resistance layer, and generates a photocurrent by a photovoltaic effect.
[0041]
As shown in FIG. 9, in the PSD 25, a P-type anti-reflection layer serving both as a light-receiving surface and a resistance layer is formed on the surface of an N-type high-resistance silicon substrate, and a pair of output electrodes is formed at both ends thereof. Have been. The back surface is an N layer on which a common electrode is formed. Therefore, when a light beam enters the PSD 25b, an electric charge proportional to the light amount is generated at the incident position. This electric charge reaches the resistive layer as a photocurrent, is divided in inverse proportion to the distance to each electrode, and is taken out from the output electrodes X1 and X2.
[0042]
Thus, the difference or ratio between the output currents extracted from the output electrodes X1 and X2 can be determined, and the incident position can be determined regardless of the light intensity and its change. The incident position of the light obtained here corresponds to the center of the light amount.
[0043]
The PSD 25 includes a one-dimensional PSD 25b and a two-dimensional PSD 25a depending on the structure of the semiconductor surface and the electrodes. The two-dimensional PSD 25a is divided into a double-sided split type and a surface split type according to the structure. Further, the surface split type includes an improved surface split type PSD 25a in which a light receiving surface and an electrode are improved. The incident position conversion formula differs depending on each structure.
[0044]
FIG. 10 is a cross-sectional view of a configuration example of the double-sided split type PSD 25a. FIG. 10A shows a plan view of the PSD 25a. FIG. 9B shows a cross-sectional view of the PSD 25a.
The double-sided split type PSD 25a has a configuration in which the N layer of the one-dimensional PSD 25b shown in FIG. 9 is also a resistance layer similarly to the P layer, and the mounting directions of the resistance layers (P layer and N layer) on both surfaces are perpendicular to each other. Has become.
[0045]
In the two-dimensional PSD 25a, the output electrodes are X1, X2, Y1, and Y2, and a position signal in the X-axis direction is output from the electrode on the front surface, and a position signal in the Y direction is output from the electrode on the back surface.
In this way, the double-sided split type PSD 25a realizes excellent resolution because currents having different polarities are split on both sides. The PSD 25 has a very simple configuration and operation. Since the output current is a current representing the position data itself, the X and Y position data can be obtained immediately.
[0046]
With this configuration, the position measurement accuracy of the PSD 25 does not greatly change due to changes in temperature and humidity. Further, unlike the CCD, there is no need to perform complicated processing of hardware and software after capturing image data. Furthermore, the PSD 25 has a higher resolution than a CCD, and can take a measurement unit from 0.5 micrometers to meters. In the PSD 25, since the center of gravity of the amount of light currently received is obtained, the position data does not change unless the shape changes. Therefore, even if the image is out of focus, if the image is uniformly spread, accurate position data can be obtained, and stable position measurement can be performed.
[0047]
As described above, the two-dimensional PSD 25a detects the position data of X and Y with one PSD 25a, but the one-dimensional PSD 25b detects the detection of the X position and the Y position information with different PSDs 25b. That is, in order to obtain information on the vertical position and the horizontal position, the position is detected by the two PSDs 25b. As described above, when the two-dimensional PSD 25a or the one-dimensional PSD 25b is used, it is not necessary to detect the tilt in the vertical direction or the horizontal direction with respect to the screen 20 (projection plane) by using the above-described tilt detecting means. Absent.
[0048]
Next, an image display operation in the projector 11 according to the present invention will be described.
[0049]
The image display according to the present invention performs image processing for inputting an image signal for capturing an image signal from an external device such as a personal computer or a video device or a built-in image memory 12b, and converting the input image signal into a projection image. The projection image formed by the image processing is enlarged and projected on the screen 20 (projection plane). Next, the distance to the projection plane is measured, the focus of the projected image is automatically adjusted, and the reflected image of the focus-adjusted projected image is captured. It operates to automatically correct the distortion of the captured reflected image.
[0050]
The automatic focus adjustment is a process of receiving a reflection image (reflected light) from a projection image projected on a projection surface by image projection, measuring a distance to the projection surface, and projecting based on the measured distance value. A projection lens drive for driving the lens is performed. The distance to the projection surface is measured by using light reflected from the projection surface of light emitted from a light source (lamp) by a driving operation in image projection, and to which position of the reflected light is received by the PSD 25 (position detection element). Is calculated based on the detected position. Then, drive control of the projection lens is performed based on the calculated distance value.
[0051]
In the image input, a process of capturing a reflection image of a projection image on which focus adjustment has been appropriately performed in automatic focus adjustment is performed. As the reflection image to be captured, a test pattern in which a center point indicating the center position of the projection image and four end points indicating the four corner positions of the projection image are simultaneously or sequentially combined is used. The capture of the reflection image is performed by a light receiving unit having 25 which is also used for automatic focus adjustment. Since the PSD 25 stores the position of one point of the reflected image every time the light receiving operation is performed, for example, a total of five light receiving operations are continuously performed from the center point of the test pattern to four end points. Do.
[0052]
In the automatic distortion correction, the distortion is corrected by performing a calculation process using a keystone correction method described later from the coordinate positions of the center point and four end points of the reflection image taken into the position detection circuit by the PSD 25 (image input). Convert to image. Then, the image signal subjected to the distortion correction is sent to the image projecting means 14 and projected on the screen 20 again.
[0053]
Here, as shown in FIG. 11, the automatic focus adjusting means 16 includes a distance measuring mechanism 44 for measuring a distance between the projection lens 40 and the screen 20, and a lens driving mechanism for driving the projection lens 40. The distance measuring mechanism 44 accurately determines the distance to the screen 20 from the reflected light or the reflected image taken in by the image input means 15a, and operates the lens driving mechanism 45 so as to be in focus. The focus of the projected image is automatically adjusted.
[0054]
The processing method of the distance measuring mechanism 44 differs depending on whether the light receiving element constituting the light receiving unit 41 of the image input unit 15a is the PSD 25 or the CCD. In the case of the PSD 25, the position where the reflected light from one point (center point) of the projection image projected on the screen 20 is incident is detected, and the distance value is calculated according to the incident position.
[0055]
Then, the driving amount of the projection lens is determined based on the calculated distance value. After the driving amount is converted into an electric signal, the driving of the projection lens is controlled by the lens driving mechanism 45. On the other hand, when a CCD is used as the light receiving element, the contrast of the reflected image reflected on the screen 20 is converted into an electric signal, and the waveform is analyzed and performed.
[0056]
To briefly explain this operation, an image once formed in the center (autofocus area) of the CCD first converts the contrast into an electric signal (waveform).
This waveform is shaped into a signal waveform for analysis by an HPF (high-pass filter). When the waveform passed through the HPF is out of focus, the undulation becomes gentle, and when it is in focus, the undulation becomes steep. In the lens driving mechanism 45, the projection is performed by stopping the projection lens 40 at the position where the waveform with the steepest undulation is detected by looking at the waveform.
[0057]
In the present embodiment, the projection image directed to the screen 20 is created by the projection lens 40 and the lamp 31 of the image projection unit 14, but a dedicated light source (for example, LED) is separately provided inside the automatic focus adjustment unit 16. You may.
[0058]
As shown in FIG. 12, the automatic distortion correction control means 17 includes a keystone calculation unit 46 and a keystone correction processing unit 47. The keystone calculation section 46 receives a reflection image of the projected image after the focus adjustment by the automatic focus adjustment section 16 via the image input section 15b. The reflection image and the capture of the reflection image are omitted because they have been described in the image input means 15a, but the captured reflection image is converted into data to which predetermined coordinates detected by the PSD 25 are added.
[0059]
Then, a keystone operation described later is performed on this data, and the keystone correction processing unit corrects the distortion (trapezoidal distortion) of the frame portion of the image. The image signal corrected here is sent to the digital format unit of the image processing unit 13 shown in FIG. 3 and converted into a predetermined image format, and then transferred again to the image projection unit 14 via the digital display unit and the DMD driving unit. It is. By passing through the automatic distortion correction control means 17, characters, figures, tables and the like are exactly focused and displayed on the screen 20 as a clear image without trapezoidal distortion.
[0060]
Further, as shown in FIG. 1, the start control means 19 for controlling the start of the image input means (15a, 15b), the automatic focus adjustment means 16, the automatic distortion correction control means 17, and the inclination detection means 18 is provided inside the projector 11. Can also be provided. The activation control unit 19 includes a sensor for detecting activation of the image projection unit 14 and a timer / counter circuit. The image input unit (15a, 15b) and the automatic focus adjustment unit are interlocked with the projection by the image projection unit 14. 16. By performing a series of processes of the automatic distortion correction control means 17 and the inclination detection means 18, an image without distortion can be displayed from the beginning.
[0061]
Further, if a predetermined count value is set in the timer / counter circuit, a series of processes of the image input means (15a, 15b), the automatic focus adjustment means 16, and the automatic distortion correction control means 17 are executed at predetermined cycles. Therefore, even when the positions of the projector 11 and the screen 20 are shifted during image projection due to vibration, impact, or the like, it is possible to periodically correct the image to have no distortion.
[0062]
In addition, the operator interrupts the image input means (15a, 15b), the automatic focus adjustment means 16 and the automatic distortion correction control means 17 at an arbitrary timing without using the timer / counter circuit. Correction can be made appropriately when the screen 11 or the screen 20 is displaced.
[0063]
Next, an example of a trapezoidal distortion correction method by the automatic distortion correction control means 17 will be described with reference to FIG.
[0064]
FIG. 13A shows a case where a reflection image in which a trapezoidal distortion has occurred via the image input unit 15b is taken into the keystone calculation unit 46 of the automatic distortion correction control unit 17 via the light receiving unit 41 shown in FIG. 3 shows the image data.
[0065]
When distortion correction is applied to this image data, the center coordinate O (0,0) of the image and the end point coordinates A (xa, 4) of the image are based on the pattern 1 or pattern 2 to pattern 6 of FIG. ya), B (xb, yb), C (xc, yc), D (xd, yd) are calculated.
[0066]
As shown in FIG. 13B, the coordinates A (xa, ya) closest to the X axis from the center coordinates O (0, 0) among the calculated end point coordinates A to D and D (xd, yd), the coordinate B (xb, yb) is reduced to B1 (xb1, yb1), which is the same as the X coordinate (xa) of A, and the coordinate C (xc, yc) is the X of D. It is contracted to C1 (xc1, yc1) which becomes the same as the coordinates (xd). With the above operation, the distortion of the horizontal method of the image is corrected.
[0067]
Subsequently, the vertical distortion is corrected based on the image in which the horizontal distortion is corrected in FIG. As shown in FIG. 12C, this time, using the coordinates D (xd, yd) and C1 (xc1, yc1) as a reference in the Y-axis direction, the coordinates A (xa, ya) are the same as the Y coordinates (ya) of D. The coordinates are reduced to A2 (xa2, ya2), which is the same, and the coordinates B1 (xb1, yb1) are reduced to B12 (xb12, yb12), which is the same as the Y coordinate (yc1) of C1.
[0068]
By sequentially correcting such horizontal and vertical coordinates, it is possible to generate square image data without trapezoidal distortion as shown in FIG. In the present embodiment, an example of correcting an image in which both the horizontal method and the vertical direction are distorted has been described. It is only necessary to correct for the distorted direction.
[0069]
The keystone correction used in the automatic distortion correction control means 17 is a method conventionally used to correct keystone distortion. However, the image itself to be subjected to the keystone correction is horizontally or Since the focus is adjusted in the vertical direction and the focus is properly adjusted through the automatic focus adjustment means 16, the position and contour of the test pattern become clear, and the coordinate conversion indicating the distortion position can be accurately performed. Therefore, the automatic distortion correction by the automatic distortion correction control means 17 can be performed more reliably.
[0070]
Next, an actual correction procedure of the projector 11 of the above embodiment will be described with reference to FIG. (ST1) to (ST14) of FIG. 14 show a procedure for performing all distortion correction automatically. Hereinafter, the correction procedure will be described.
(ST1) The image display device and the screen are positioned, and the power of the image display device is turned on.
(ST2) Requests transmission of an image signal to an external device such as a personal computer or a video device or an image memory built in the image display device.
(ST3) A timer / counter for measuring an automatic execution cycle of distortion correction is started.
(ST4) It is confirmed whether or not the image signal requested in (ST2) has been input.
(ST5) Digital processing is performed on the input image signal to convert it into a projected image composed of image images.
(ST6) The projection image is projected on a screen by being put on a light source emitted from a lamp unit.
(ST7) If the projector 11 is tilted in the vertical or horizontal direction measured by the gyroscope 48a, the support means is corrected so as to match the vertical or horizontal direction of the reference light emitting axis.
(ST8) A focal length is calculated from the projection image and a reflection image of the projection image to automatically adjust the focus.
(ST9) A reflection image of the focus-adjusted projection image via a screen surface is captured.
(ST10) The distortion of the captured reflected image is corrected by a keystone correction method or the like.
(ST11, ST12) After digitally converting the corrected image signal, the image signal is re-projected on the screen via the image projection means.
(ST13) After the processing in ST10 and ST11 is completed, the value of the timer / counter is incremented or decremented by one. Here, when the count value becomes 0, the process proceeds to the next power-off procedure (ST14), but when the count value remains, it keeps turning until the count value becomes 0, and the timing for performing the distortion correction is periodically set. To measure.
[0071]
According to the operation procedure shown in FIG. 14, the distortion of the projected image is automatically corrected at the cycle set in the timer / counter, so that the projector or the screen is suitable for use where the installation is unstable or where there is a lot of vibration. ing.
[0072]
The projector 11 described above is a DLP system using a DMD. However, even if the projector 11 is a liquid crystal system using a liquid crystal panel, only the image projection unit is different, and the same focus adjustment unit and distortion correction unit are used. Can be provided. Further, the present invention can be applied to projection-type projectors other than the above-described method.
[0073]
As described above, the image display device of the present invention receives the reflected light from a plurality of light points in the projection image projected on the projection surface, and the projection unit that projects the projection image toward the projection surface. A two-dimensional PSD, a position detection circuit that detects positions of the plurality of light spots in the projection image based on an output signal from the two-dimensional PSD, and a position of the plurality of light spots detected by the position detection circuit Control means for detecting a distortion of a projected image projected on the projection surface by the image projection means based on the image data and correcting the distortion.
[0074]
Here, the image display device of the present invention detects the position of the light spot by the two-dimensional PSD that receives the reflected light from the plurality of light spots in the projected image projected on the projection surface, and corrects the distortion of the projected image. I do. This makes it possible to correct the distortion of the projected image projected on the projection surface accurately and efficiently at a high detection speed.
[Brief description of the drawings]
FIG. 1 is an overall block diagram of an image display device according to the present invention.
FIG. 2 shows a test pattern used for focus adjustment and distortion correction.
FIG. 3 shows a block diagram of an image processing means in the image display device.
FIG. 4 is a configuration diagram of an image projection unit in the image display device.
FIG. 5 shows a configuration diagram of an image projection unit in the image display device.
FIG. 6 is a front perspective view of the projector according to the invention.
FIG. 7 is a block diagram of an image input unit in the image display device.
FIG. 8 is a block diagram of an inclination detecting means in the image display device.
FIG. 9 is a cross-sectional view illustrating a basic configuration of a PSD (one-dimensional).
FIG. 10 is a sectional view of a configuration example of a double-sided split PSD.
FIG. 11 is a block diagram of an automatic focus adjustment unit in the image display device.
FIG. 12 is a block diagram of an automatic distortion correction unit in the image display device.
FIG. 13 is an explanatory diagram showing the principle of keystone correction.
FIG. 14 is a flowchart illustrating an operation procedure of the image display device including the automatic distortion correction control unit.
[Explanation of symbols]
11 Projector (image display device)
12 Image signal input means
13 Image processing means
14 Image projection means
15a Image input means
16 Automatic focus adjustment means
17 Automatic distortion correction control means
18 Tilt detecting means
20 screen (projection surface)
25 PSD
25a 2D PSD
25b one-dimensional PSD
26 Position detection circuit
41 Receiver
44 Distance measuring mechanism
45 Lens drive mechanism

Claims (10)

Projecting means for projecting a projection image toward a projection surface;
A two-dimensional PSD for receiving reflected light from a plurality of light points in a projection image projected on the projection surface;
A position detection circuit that detects positions of the plurality of light spots in the projection image based on an output signal from the two-dimensional PSD;
Control means for detecting distortion of a projection image projected on the projection surface by the image projection means based on the positions of the plurality of light spots detected by the position detection circuit, and correcting the distortion;
An image display device comprising: Projecting means for projecting a projected image toward a projection surface,
Inclination detection means for detecting the inclination of the projection axis of the projection means with respect to the projection surface, and a PSD for receiving reflected light from a plurality of light points in a projection image projected on the projection surface;
A position detection circuit that detects positions of the plurality of light spots in the projection image based on an output signal from the PSD;
Based on the detection result detected by the tilt detecting means, a distortion caused by a tilt in any one of a vertical direction and a horizontal direction of a projected image projected on the projection surface is detected, and the distortion is corrected. Control means for detecting distortion in the other direction of the projection image projected on the projection surface based on the detected positions of the plurality of light spots and correcting the distortion,
An image display device comprising: The image display device according to claim 2, wherein the inclination detecting means is a gyroscope. 3. The tilt detecting device according to claim 2, wherein the tilt detecting device detects a tilt of the light projecting axis of the projecting device with respect to the projection surface by detecting a tilt of the device main body with respect to a supporting device that supports the device main body. Image display device. The image display unit according to claim 2, wherein the PSD is a one-dimensional PSD. The image display unit according to claim 2, wherein the PSD is a two-dimensional PSD. Projecting means for projecting a projected image toward a projection surface,
Two PSDs for receiving reflected light from a plurality of light points in a projected image projected on the projection surface;
The plurality of vertical positions in the projected image are detected based on an output signal from one of the two PSDs, and the horizontal positions of the plurality of light spots are detected based on the output of the other PSD. Position detection circuit,
Control means for detecting and correcting distortion of a projection image projected on the projection surface by the image projection means based on the positions of the plurality of light spots detected by the position detection circuit;
An image display device comprising: The image display device according to claim 7, wherein each of the two PSDs is a one-dimensional PSD. 8. The image display device according to claim 1, wherein the control unit detects and corrects the distortion of the projection image at predetermined time intervals. The PSD is
At least one pair of electrodes,
Photoelectric conversion means for receiving a spot-like light from the light spot and generating a current supplied to the at least one pair of electrodes,
A resistor that conducts the current between the at least one pair of electrodes,
The image display device according to claim 1, further comprising:

Images