JP2003348498A - Image display method and image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display method including a series of processing steps of accurately detecting distortion of an image projected on a projection screen and correcting the distortion on the basis of the result of detection. <P>SOLUTION: The image display method of this invention includes: an image signal input step S1 of capturing the image signal; an image processing step S2 of converting the captured image signal into a projection image; an image projection step S3 of projecting the projected image toward the projection screen with magnification; an automatic focus adjustment step S14 of measuring a distance up to the projection screen so as to automatically adjust the focus of the projected image; an image input step S15 of capturing a reflected image of the projected image whose focus is properly adjusted in the automatic focus adjustment step S14; and an automatic distortion correction step S16 of detecting the distortion of the reflected image captured by the image input step S15 to automatically correct the distortion. The method sequentially executes the steps above to quickly and surely correct the distortion of the projected image. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projector for projecting characters, diagrams, and the like input from a personal computer, a video device, or the like onto a screen, and in particular, to display a clear image with proper focus adjustment and distortion correction. The present invention relates to an image display method and an image display device.

[0002]

2. Description of the Related Art Conventionally, there is known an image display device (projector) for enlarging and projecting an image on a screen.
This projector 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 This is a type that projects an image from. For the front type, 10
Although it is possible to display a large screen of 0 inches or more, it is necessary to increase the projection distance accordingly. In addition, the image display device main body and a projection surface such as a screen are formed separately, and the arrangement direction and the arrangement distance thereof can be set arbitrarily. If the distance is shifted, the four corners of the projected image will be distorted in a trapezoidal shape. As means for correcting this distortion, the operator manually operates the adjusting device of the image display device main body while watching the projected image on the screen, and the projection light and projection light emitted from the projection surface of the image display device. There is one that automatically detects the amount of distortion from the light reflected from the surface and performs distortion correction (see Japanese Patent Application Laid-Open No. H8-9309).

[0003]

However, in the conventional distortion correction methods described above, the operation is often performed in a state where the projected image itself is not properly focused.
For this reason, in the type in which the operator manually performs the correction, the distortion correction is performed without sufficiently recognizing the outline of the image. Therefore, in order to correct the distortion, the correction operation has to be performed repeatedly. Also,
In a device that automatically corrects distortion using reflected light from a projection surface (Japanese Patent Laid-Open No. 9309/1996), the focus of an image captured from the projection surface is shifted. Correction will be applied to the image that has been shifted. Therefore, there are problems that the distortion correction processing takes time and distortion is not accurately corrected.

Accordingly, a first object of the present invention is to provide an image display method including a series of processing steps for accurately detecting distortion of an image projected on a projection surface and performing correction based on the detection result. To provide.

A second object of the present invention is to provide an image display apparatus which detects and corrects distortion of an image projected on a projection surface quickly and accurately and reduces the number of parts required for the detection. To provide.

[0006]

According to a first aspect of the present invention, there is provided an image display method comprising the steps of: inputting an image signal for capturing an image signal; and converting the captured image signal into a projected image. An image processing step of converting, an image projection step of enlarging and projecting the projection image toward a projection surface, an automatic focus adjustment step of measuring a distance to the projection surface and automatically adjusting a focus of the projection image, An image input step of capturing a reflection image of the projection image properly adjusted in focus by the focus adjustment step; and an automatic distortion correction step of automatically detecting and correcting distortion of the reflection image captured in the image input step. It is characterized by.

According to the present invention, when the projected image projected on the projection surface through the image signal inputting step, the image processing step, and the image projecting step is distorted, the focus of the projected image is firstly adjusted by the automatic focusing step. Is adjusted in the automatic distortion correction step after the adjustment of the correction is performed properly, so that the correction processing in the automatic distortion correction step can be performed quickly and accurately.

According to a second aspect of the present invention, there is provided an image display method according to the first aspect of the present invention, wherein the projection image whose focus has been adjusted in the automatic focus adjustment step is manually distorted. A manual distortion correction step for performing correction is provided.

According to a third aspect of the present invention, in the image display method according to the first aspect of the present invention, focus adjustment is manually performed on the projection image projected in the image projection step. A manual focus adjustment step and a manual distortion correction step of manually performing distortion correction after the manual focus adjustment step are provided.

According to the second aspect of the present invention, up to the focus adjustment of the projected image can be automatically performed, and only the distortion correction can be performed by manual operation. According to the third aspect of the present invention, it is possible to manually operate from focus adjustment to distortion correction while visually confirming the projection image projected in the image projection step. In this way, by making some of the entire steps manually operable, it is possible to simplify the apparatus configuration and reduce costs.

When the manual distortion correction step is provided, an operation detection step is provided for detecting that the distortion correction operation has been started, and an automatic focus adjustment step is executed based on the detection result of the operation detection step. For this reason,
Distortion correction can be performed manually while viewing the properly focused projected image. In addition, when a focus adjustment instruction step for instructing to perform focus adjustment is provided according to the result of the operation detection step, even if the focus adjustment is manually performed, the focus adjustment must be performed before distortion correction is performed. The operating procedure is ensured because the adjustment is guided.

Further, according to a sixth aspect of the present invention, there is provided an image display device, comprising: an image signal input unit for receiving an image signal; an image processing unit for converting the captured image signal into a projection image; Image projection means for enlarging and projecting the image onto a plane, automatic focus adjustment means for automatically adjusting the focus of the projection image by measuring the distance to the projection plane, and the projected image properly focused by the automatic focus adjustment means And an automatic distortion correcting means for detecting distortion of the captured reflected image and automatically correcting the distortion.

According to the present invention, when the projected image projected on the projection surface via the image signal input means, the image processing means, and the image projecting means is distorted, the focus of the projected image is firstly adjusted by the automatic focus adjusting means. Is appropriately adjusted and then corrected by the automatic distortion correction means, so that the correction processing in the automatic distortion correction means can be performed quickly and accurately.

The automatic focus adjusting means includes a distance measuring mechanism for measuring a focal length to a projection surface based on a reflection image of the projected image projected by the image projecting means, and automatically adjusts a projection lens according to the focal length. The lens drive mechanism is provided. The distance measuring mechanism employs a position detecting element (PSD) or an image pickup element (CCD) as a light receiving unit, so that the distance to the projection plane can be accurately measured, and the lens driving can be accurately adjusted based on the measurement result. Can be transmitted to the mechanism.

The automatic distortion correcting means detects the amount of distortion from the reflected image captured by the image input means using the PSD or CCD as a light receiving unit, and automatically corrects the distortion so as to absorb the amount of distortion. Is provided. The distortion correction mechanism is the PSD or CCD
Has the function of calculating the coordinates of each pixel of the reflected image captured in step 2 and converting the image into a clear image without distortion using a keystone correction method.

Further, at least one of the light emitting unit provided in the image projection unit and the light receiving unit provided in the image input unit may be provided with a light emitting unit for focus adjustment or a light receiving unit for focus adjustment provided in the automatic focus adjusting unit. By double use,
The number of parts is reduced, and the apparatus configuration is simplified and the cost is reduced.

Further, a case is provided in which start-up control means is provided so that the image input means, automatic focus adjustment means and automatic distortion correction means are started in conjunction with the start of projection from the image projection means. Can automatically perform focus adjustment to distortion correction every time the projection operation is started. Further, if the activation control means is activated at a predetermined period or at an arbitrary timing even during the projection operation, even if the position of the image display device main body or the screen is displaced due to some vibration or impact, it follows the deviation. An optimal image display with focus adjustment and no distortion can always be performed.

According to a thirteenth aspect of the present invention, in the image display device, after passing through the image signal input means, the image processing means, the image projection means and the automatic focus adjustment means, the distortion of the projected image is corrected by the manual distortion correction means. Although it is configured to manually perform the operation, the operation is detected by the operation detection unit that detects that the manual distortion correction is started, and further, the operation control unit that executes the automatic focus adjustment unit based on the detection result is provided. With this arrangement, the projected image is always in focus even while the distortion correction is manually performed, and the distortion correction operation can be performed easily and accurately.

An image display apparatus according to a fourteenth aspect of the present invention has a configuration in which a manual focus adjustment unit and a manual distortion correction unit are performed after passing through an image signal input unit, an image processing unit, and an image projection unit. However, the operator can be instructed to perform focus adjustment first by the operation detection unit and the focus adjustment instruction unit that detect that the manual distortion correction has been started. For this reason, even in the device configuration in which the focus adjustment and the distortion correction can be manually operated, the operator can perform the operation without being lost in the order of the focus adjustment and the distortion correction.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an image display method and an image display device according to the present invention will be described in detail with reference to the accompanying drawings. Here, FIGS. 1 to 3 are flowcharts showing the flow of processing in the image display method according to the present invention.

(Image Display Method) As shown in FIG. 1, in the image display method according to the present invention, an image signal input step (S1) for receiving an image signal from an external device such as a personal computer or a video device or a built-in image memory. ), An image processing step (S2) of converting the image signal into a projection image, and an image projection step (S3) of enlarging and projecting the projection image formed by the image processing step (S2) on a projection surface (screen). An image projection flow (F1), an automatic focus adjustment step (S14) for automatically adjusting the focus of the projection image by measuring the distance to the projection plane, and an image input step for capturing a reflection image of the focus adjusted projection image ( S15) and an image correction flow (F) including an automatic distortion correction step (S16) for automatically correcting the distortion of the captured reflected image.
2).

The image projection flow (F1) is a general processing step provided in a conventional image display device (projector), while the image correction flow (F2) is a processing step unique to the present invention. I have. Hereinafter, the image correction flow (F2) will be described in detail.

In the automatic focus adjustment step (S14),
A process of receiving a reflection image (reflected light) from the projection image projected on the projection surface in the image projection step (S3), measuring a distance to the projection surface, and projecting based on the measured distance value A projection lens driving process 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 the image projection step (S3), and the reflected light is used as a position detection element (PSD). The position at which light is received is detected, and calculation is performed based on the detected position.
Then, drive control of the projection lens is performed based on the calculated distance value.

In the image input step (S15), a process of capturing a reflection image of the projected image properly focused in the automatic focus adjustment step (S14) is performed. As the reflection image to be captured, a test pattern in which a center point indicating the center position of the projected image and four end points indicating the four corner positions of the projected image are simultaneously or sequentially combined is used. The reflection image is captured by a light receiving unit including a PSD or an image pickup device (CCD) used in the automatic focus adjustment step (S14). When the PSD is used, each time a light receiving operation is performed, the position of one point of the reflected image is stored. Therefore, a total of five light receiving operations from the center point of the test pattern to four end points are performed. Must be performed continuously. On the other hand, C
In a CD, the entire image of the projection image is stored as it is as pixel information in a single operation.

The automatic distortion correction step (S16) comprises:
Using the keystone correction method described later, arithmetic processing is performed from the coordinates of the center point and the four end points of the reflection image captured in the image input step (S15) to convert the image into a distortion-corrected image. Then, the image signal whose distortion has been corrected is sent from the automatic distortion correction step (S16) to the image projection step (S3), and is again projected on the projection surface.

The above processing steps are for automatically performing all the steps from the image projection step (S3) to the focus adjustment and the distortion correction. The steps up to the automatic focus adjustment step (S14) are automatically performed, and the distortion is corrected. A method for shifting to a manual distortion correction step (S18) for manually performing correction, and a manual focus adjustment step (S17) for manually performing focus adjustment and distortion correction after the image projection means (S3).
It is also possible to take a method of shifting to the manual distortion correction step (S18) from FIG.

FIG. 2 shows a processing flow for manually executing the distortion correction. In this processing flow, after the image signal input step (S1), the image processing step (S2), and the image projection step (S3), an operation detection step (S24) for detecting that the distortion correction has been manually started is provided. This operation detection step (S24)
When the manual operation of the distortion correction is detected by the operation, the operation in the manual distortion correction step (S26) can be performed via the automatic focus adjustment step (S25). According to this processing flow, when the operator manually performs the distortion correction, the focus of the projection image to be corrected is always properly adjusted, so that the distortion correction can be accurately performed visually. In the operation detection step (S24), if the operation start of the distortion correction is not detected, the projection image in the initial image projection step (S3) is projected on the projection surface without passing through the focus adjustment and the distortion correction. Will be.

FIG. 3 shows a processing flow for manually performing the focus adjustment and the distortion correction. In this processing flow, after the image signal inputting step (S1), the image processing step (S2), and the image projecting step (S3), the manual operation of the distortion correction is started as shown in FIG. Operation detection step to detect (S3
4) is provided, and when a manual operation of distortion correction is detected in the operation detection step (S34), a manual focus adjustment step (S36) is performed through a focus adjustment instruction step (S35) for instructing to perform focus adjustment. ) And the manual distortion correction step (S37) can be operated. According to this processing flow, when the focus adjustment and the distortion correction are both manually operable, when the operator manually performs the distortion correction, the operator performs the focus adjustment instruction step so as to perform the focus adjustment first. An instruction can be received in (S35), and the operation procedure can be performed reliably without mistake. As shown in FIG. 2, if the manual operation of the distortion correction is not detected in the operation detection step (S34), the initial image projection step (S3) is performed without passing through the focus adjustment and the distortion correction. Is projected on the projection surface as it is.

(Image Display Apparatus) Next, FIGS.
The configuration of an image display device that realizes the image display method shown in FIG. 1 will be described with reference to FIGS. This image display device is a data projector (hereinafter, referred to as a projector) used by connecting to a personal computer or the like. Projectors include a liquid crystal system using a liquid crystal panel and a DLP (digital write processing) system using a DMD (digital micromirror device). The following embodiment is a projector using the latter DLP system. is there.

FIG. 4 shows the configuration of the first embodiment of the 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, and an image input unit (15
a, 15b), an automatic focus adjusting unit 16 and an automatic distortion correcting unit 17, and a light source (lamp unit 24) provided in the image projecting unit 14. In addition to the projector 11, a projection surface (screen 20) for displaying an image image projected by the image projection means 14 is provided outside.

The image signal input means 12 realizes the image signal input step (S1) described in the above image display method, and includes an external device 12a such as a personal computer or a video device or an image memory built in the projector 11. 1
An interface unit for taking in an image signal from 2b is provided. In this interface unit, 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, it is subjected to A / D conversion processing and transferred to the image processing means 13. The image signal captured by the image signal input unit 12 includes a test image used in an automatic focus adjustment unit 16 and an automatic distortion correction unit 17 to be described later, in addition to original characters and figures. In this test image, as shown in FIG. 5, patterns 1 to 6 are prepared in which the central portion and the four corners emit white light in a point-like manner.
Note that the pattern 1 is provided by an image input means (15
The light receiving elements mounted on the light receiving unit 41 in (a, 15b) are used when the light receiving element is a CCD, and the patterns 2 to 6 are used when the light receiving element is a PSD.

As shown in FIG. 6, the image processing means 13
A digital formatter, a digital display, and a DMD driver are provided mainly with a digital processor (CPU), and various digital signal processing is performed on image signals that have passed through the image signal input means 12 and the automatic distortion correction means 17 described later. Is applied. Well-known image processing techniques are used for the processing content according to the type of image to be displayed, but 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. And, by the memory control unit,
The image data stored in the frame memory is taken out, and a lamp unit 24 and an image projection
Is projected as an image of light.

The image projection means 14 is provided with the image processing means 1.
3 converts the image converted by the lamp unit 2
4 is provided with a mechanism for projecting the light emitted from the projection lens 40 onto the screen 20 at a predetermined distance from the projection lens 40. FIGS. 7 and 8 show the structure of the image projecting means 14, in which the light emitting surface 34 of the lamp 31 constituting the lamp unit 24 extends from the color wheel 35 to the integrator 3.
6, condenser lens 37, DMD 38 (digital micromirror device), mirror 39, projection lens 4
They are arranged in the order of 0. The lamp unit 24 includes:
It comprises a lamp 31 that emits white light, and a semicircular reflector 32 surrounding the back 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 disc-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. 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-compact aluminum movable mirrors are formed. The number of the movable mirrors is provided for each pixel 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.

Next, in the projector 11 of the present invention, the image input means (15a, 15b), the automatic focus adjusting means 16, and the automatic distortion correction which are the main means for enabling the distortion of the projected image to be corrected accurately and quickly. The means 17 will be described in detail. FIG. 4 shows the image input means (15
a, 15b) are shown, but in an actual device configuration, one image input device is switched to switch the automatic focus adjustment means 1
6 and the automatic distortion correcting means 17 incorporate reflected light or a reflected image.

The image input means (15a, 15b)
As shown in FIG. 9, the light receiving unit 41, the signal processing unit 42,
An A / D converter 43 is provided. The light receiving section 41 receives light reflected by the screen 20.
SD (Position Sensitive Detector) or CCD
(Charge Coupled Device). The PSD is called a so-called position detecting element, and is used in an automatic focus adjusting unit 16 to be described later.
The incident position of the light reflected at 0 is detected, and the projection position of the projection lens 4 provided in the image projection means 14 is determined based on the incident position.
The distance from 0 to the screen 20 is calculated. The automatic distortion correcting 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. 5 and converts them into coordinates for performing distortion correction. When the light receiving element of the light emitting unit 41 is a PSD, the patterns 2 to 6 are sequentially taken in from the pattern 2 continuously projected from the image projecting unit 14. On the other hand, when a CCD is used as the light receiving element of the automatic focus adjustment unit 16 instead of the PSD, the contrast of the received light is converted into an electric signal, and the waveform thereof is analyzed to focus the image projected on the screen 20. Adjustments are made. When the CCD is used as the light receiving element of the automatic distortion correcting means 17, the pattern 1 is stored as an image image as it is. The signal processing unit 42 converts the analog photocurrent received by the light receiving unit 41 into a signal having an analog voltage level, and the A / D conversion unit 43 converts the analog voltage signal into a digital signal. Are transferred to the automatic focus adjustment means 16 and the automatic distortion correction means 17.

As shown in FIG. 10, 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. 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 a PSD or a CCD. Screen 2 for PSD
The position where the reflected light from one point (center point) of the projected image projected on 0 is incident is detected, and the distance value is calculated according to the incident position. 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, C
When a CD is used, the contrast of the reflected image reflected on the screen 20 is converted into an electric signal, and the waveform is analyzed and performed. To briefly explain this operation, first, the CCD
The image once formed in the central portion (autofocus area) of the image is converted 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. 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 means 14, but a dedicated light emitting source (for example, LE
D) may be separately provided inside the automatic focus adjustment means 16.

As shown in FIG. 11, the automatic distortion correction means 17 includes a keystone calculation section 46 and a keystone correction processing section 4.
7 is provided. The keystone operation unit 46 is connected to the automatic focus adjustment unit 16 via the image input unit 15b.
Captures the reflected image of the projected image whose focus has been adjusted. 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 are given.
Then, a keystone calculation 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 section of the image processing means 13 shown in FIG. 6, and after being converted into a predetermined image format,
The image is transferred to the image projecting unit 14 again via the digital display unit and the DMD driving unit. This automatic distortion correction means 1
By passing through the screen 7, characters, figures, tables and the like are focused on each other and displayed on the screen 20 as a clear image without trapezoidal distortion.

As shown in FIG. 4, a start control means 19 for controlling the start of the image input means (15a, 15b), the automatic focus adjustment means 16 and the automatic distortion correction means 17.
May be provided in the projector 11. The activation control means 19 includes a sensor for detecting activation of the image projection means 14 and a timer / counter circuit. The image input means (15a, 1
5b), automatic focus adjustment means 16 and automatic distortion correction means 1
By performing the series of processes in step 7, an image without distortion can be displayed from the beginning. Further, the timer /
If a predetermined count value is set in the counter circuit,
Since a series of processes of the image input means (15a, 15b), the automatic focus adjustment means 16 and the automatic distortion correction means 17 are executed at predetermined intervals, the position of the projector 11 or the screen 20 may be changed during the image projection. Therefore, even if the image is displaced, the image can be periodically corrected to have no distortion. Note that an operator interrupts the image input means (15a, 15b), the automatic focus adjustment means 16 and the automatic distortion correction means 17 at an arbitrary timing without passing through the timer / counter circuit, so that the projector 11
When the screen 20 is displaced, the correction can be appropriately performed.

(Distortion Correction Method) Next, an example of a method for correcting trapezoidal distortion by the automatic distortion correction means 17 will be described with reference to FIG. FIG. 12A shows the image input means 1.
FIG. 10 shows image data when a reflection image in which a trapezoidal distortion has occurred through 5b is taken into the keystone calculation unit 46 of the automatic distortion correction unit 17 via the light receiving unit 41 shown in FIG. To apply distortion correction to this image data, the pattern 1 or the pattern 2 to 2 of FIG.
Based on the pattern 6, the center coordinates O (0, 0) of the image and the end point coordinates A (xa, ya), B (xb, yb), C (x
c, yc) and D (xd, yd) are calculated. FIG.
As shown in (b), the coordinates A (xa, ya) and D (xd, yd) closest to the X axis first from the center coordinates O (0, 0) among the calculated end point coordinates A to D. Is defined as a reference in the X-axis direction, the coordinate B (xb, yb) is the X coordinate (xa) of A.
Is reduced to B1 (xb1, yb1) which becomes the same as the coordinate C (xc, yc) becomes the same as the X coordinate (xd) of D
1 (xc1, yc1). With the above operation, the distortion of the horizontal method of the image is corrected. Subsequently, FIG.
The vertical distortion is corrected based on the image in which the horizontal distortion has been corrected. 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. It is contracted to A2 (xa2, ya2) which becomes the same, and the coordinate B1 (xb1, yb1) becomes the Y coordinate (yc) of C1.
It is contracted to B12 (xb12, yb12) which is the same as 1). 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. However, as a result of calculating the coordinates in the keystone calculation unit 46, if distortion is detected only in the horizontal direction or only in the vertical direction, It is only necessary to correct for the distorted direction.

The keystone correction used in the automatic distortion correction means 17 is a method conventionally used for correcting keystone distortion. The image itself to be subjected to the keystone correction is used by the automatic focus adjustment means 16 in advance. Since the focus adjustment is properly performed throughout the test pattern, the position and contour of the test pattern become clear, and the coordinate conversion indicating the distortion position can be accurately performed. For this reason, the automatic distortion correction by the automatic distortion correction means 17 can be performed more reliably.

(Manual Distortion Correction) Next, a configuration in which only the distortion correction can be manually operated and an embodiment in which both the focus adjustment and the distortion correction can be manually operated will be described with reference to FIGS. FIG. 13 shows a projector 51 of a second embodiment including a manual distortion correction unit 54 for manually performing distortion correction. The projection onto the screen 20 is performed via the image signal input unit 12, the image processing unit 13, and the image projection unit 14, similarly to the projector 11 of the first embodiment, and thereafter, the operation detection unit 52, the operation control unit 53
Manual distortion correcting means 5 through automatic focus adjusting means 16 from
4 is performed manually. The operation detecting means 52
Is for detecting that the operator has operated the switches for distortion adjustment to correct the distortion by looking at the projected image projected on the screen 20. When it is detected that the operation has been performed, the process proceeds to the next operation control unit 53. However, when the operation has not been performed, the projection by the image projection unit 14 is continued as it is. The operation control means 53 is controlled based on the detection signal from the operation detection means 52 so as to enable the manual operation in the manual distortion correction means 54 from the automatic focus adjustment of the projected image by the automatic focus adjustment means 16. You. As described above, since the focus of the projected image is automatically adjusted at the same time that the operator manually starts the distortion correction, the distortion can be surely corrected while always looking at the projected image whose focus has been appropriately adjusted.

(Manual Focus Adjustment, Manual Distortion Correction) FIG. 14 shows a projector 61 of a third embodiment in which focus adjustment is manually performed in the projector 51 of the second embodiment shown in FIG. In this configuration, an operation instructing unit 62 for giving an instruction to the operator to adjust the focus of the projection image is executed after the operation detecting unit 52 for detecting that the distortion correction is manually started. The operation instructing means 62 may be appropriately selected from a method of visually confirming by blinking an LED or the like provided near a switch provided in the liquid crystal display unit or the manual focus adjusting means 63, or a method of recognizing by voice such as a buzzer. Used as The operator can proceed to the manual focus adjusting means 63 instructed by the operation instructing means 62 and thereafter execute the manual distortion correcting means 54. As described above, in the case where both the focus adjustment and the distortion correction are performed manually, since the operation detecting means 52 and the operation instructing means 62 are provided, even if the operator who operates the projector 61 for the first time does not perform the distortion correction, Since the focus adjustment can be performed without forgetting, the distortion correction can be performed quickly and reliably.

(Operation Procedure by Automatic Distortion Correction) Next, an actual operation procedure of the projector 11 of the first embodiment will be described with reference to FIGS. (ST of FIG. 15)
1) to (ST13) show the procedure for performing all distortion correction automatically. Hereinafter, description will be given according to the operation procedure. (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 the image signal into a projected image composed of image images. (ST6) The projection image is mounted on a light source emitted from a lamp unit and projected on a screen. (ST7) A focal length is calculated from the projection image and a reflection image of the projection image to automatically adjust the focus. (ST8) A reflection image of the focus-adjusted projection image via a screen surface is captured. (ST9) The distortion of the captured reflected image is corrected by a keystone correction method or the like. (ST10, 11) After the corrected image signal is converted into a digital signal, the image signal is re-projected on the screen via the image projection means. (ST12) 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 (ST13). However, 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.

(Operation Procedure by Manual Distortion Correction) FIG. 16 shows an operation procedure when the distortion correction is manually operated. Hereinafter, description will be given according to the operation procedure. (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) It is confirmed whether or not the image signal requested in (ST2) has been input. (ST4) Digital processing is performed on the input image signal to convert the image signal into a projection image composed of image images. (ST5) The projection image is projected on a screen by a light source emitted from a lamp unit. (ST6) It is determined whether or not the projection image projected on the screen has distortion or whether distortion correction is necessary. If there is no distortion, the projection is continued as it is. on the other hand,
If it is determined that there is distortion, the process proceeds to the next focus adjustment step. (ST7) A focal length is calculated from the projection image and a reflection image of the projection image to automatically adjust the focus. (ST8) A reflection image of the focus-adjusted projection image via a screen surface is captured. (ST9) The distortion of the captured reflected image is manually corrected. (ST10, 11) After the corrected image signal is converted into a digital signal, the image signal is re-projected on the screen via the image projection means.

According to the operation procedure shown in FIG. 15, since the distortion of the projected image is automatically corrected at the cycle set in the timer / counter, the projector or the screen is used in an unstable place or in a place with a lot of vibration. Suitable for the case. According to the operation procedure shown in FIG. 16, distortion correction can be performed while viewing the projected image projected on the screen with the focus adjusted, so that distortion correction can be performed more accurately.

The projectors 11 and 5 shown above
Reference numerals 1 and 61 denote a DLP system using a DMD. However, even a liquid crystal projector using a liquid crystal panel has the same focus adjustment unit and distortion correction unit except for the image projection unit. Can be In addition, the present invention can be applied to projection-type projectors other than such a system.

[Brief description of the drawings]

FIG. 1 is an overall flowchart of an image display method according to the present invention.

FIG. 2 is a flowchart illustrating a case where distortion correction is manually enabled in the image display method.

FIG. 3 is a flowchart in a case where focus adjustment and distortion correction can be manually operated in the image display method.

FIG. 4 is an overall block diagram of an image display device according to the present invention.

FIG. 5 is a test pattern used for focus adjustment and distortion correction.

FIG. 6 is a block diagram of an image processing unit in the image display device.

FIG. 7 is a configuration diagram of an image projection unit in the image display device.

FIG. 8 is a configuration diagram of an image projection unit in the image display device.

FIG. 9 is a block diagram of an image input unit in the image display device.

FIG. 10 is a block diagram of an automatic focus adjustment unit in the image display device.

FIG. 11 is a block diagram of an automatic distortion correction unit in the image display device.

FIG. 12 is an explanatory diagram showing the principle of keystone correction.

FIG. 13 is a block diagram illustrating a configuration of an image display device according to a second embodiment of the present invention.

FIG. 14 is a block diagram illustrating a configuration of an image display device according to a third embodiment of the present invention.

FIG. 15 is a flowchart illustrating an operation procedure of the image display device including the automatic distortion correction unit.

FIG. 16 is a flowchart illustrating an operation procedure of the image display device including the manual distortion correction unit.

[Explanation of symbols]

S1 Image signal input step S2 Image processing step S3 Image projection step S14 Automatic focus adjustment step S15 Image input step S16 Automatic distortion correction step 11, 51, 61 Projector (image display device) 12. Image signal input means 13 Image processing means 14 Image projection means 15a, 15b Image input means 16 Automatic focus adjustment means 17 Automatic distortion correction means 20 screen (projection surface) 41 Receiver 44 Distance measuring mechanism 45 Lens drive mechanism 52 Operation detection means 53 Operation control means 54 Manual distortion correction means 62 Operation instruction means 63 Manual focus adjustment means

Continuation of front page    F term (reference) 2K103 AA08 AA13 AA16 AA22 AB08                       BB07 BC44 CA35                 5C058 AA06 AA18 BA27 BB13 BB25                       EA01 EA02 EA26 EA27 EA31                       EA42

Claims (14)

[Claims] An image signal inputting step of capturing an image signal; an image processing step of converting the captured image signal into a projection image; an image projection step of enlarging and projecting the projection image toward a projection surface; An automatic focus adjustment step of automatically adjusting the focus of the projected image by measuring the distance to the projection surface, and an image input step of capturing a reflected image of the projected image properly adjusted by the automatic focus adjustment step,
An automatic distortion correction step of detecting and automatically correcting distortion of the reflected image captured in the image input step. 2. An image signal inputting step of capturing an image signal, an image processing step of converting the captured image signal into a projection image, an image projection step of enlarging and projecting the projection image toward a projection surface, An image display method, comprising: an automatic focus adjustment step of automatically adjusting a focus of a projection image by measuring a distance to a projection surface; and a manual distortion correction step of manually correcting distortion of the focus-adjusted projection image. 3. An image signal inputting step of capturing an image signal, an image processing step of converting the captured image signal into a projection image, an image projection step of enlarging and projecting the projection image toward a projection surface, An image display method, comprising: a manual focus adjustment step of manually adjusting a focus of a projection image; and a manual distortion correction step of manually correcting distortion of the focus-adjusted projection image. 4. An image signal inputting step of capturing an image signal, an image processing step of converting the captured image signal into a projection image, an image projection step of enlarging and projecting the projection image toward a projection surface, An operation detecting step of detecting an operation of manually correcting the distortion of the projection image, and after detecting that the operation of the distortion correction has been performed by the operation detecting step, the distance to the projection plane is measured to measure the projection image. An image display method, comprising: an automatic focus adjustment step of automatically adjusting the focus of the image; and a manual distortion correction step of manually correcting the distortion of the projected image subjected to the focus adjustment. 5. An image signal inputting step of capturing an image signal, an image processing step of converting the captured image signal into a projection image, an image projection step of enlarging and projecting the projection image toward a projection surface, An operation detecting step of detecting an operation of manually correcting the distortion of the projected image, and a focus for instructing to perform a focus adjustment of the projected image after detecting that the operation of the distortion correction has been performed by the operation detecting step. An image display method, comprising: an adjustment instruction step; a manual focus adjustment step of manually adjusting the focus of the projection image; and a manual distortion correction step of manually correcting distortion of the projection image on which the focus adjustment has been performed. 6. An image signal input unit for capturing an image signal, an image processing unit for converting the captured image signal into a projection image, an image projection unit for enlarging and projecting the projection image toward a projection surface, Automatic focus adjusting means for automatically adjusting the focus of the projected image by measuring the distance to the projection surface; image input means for capturing a reflected image of the projected image properly focused by the automatic focus adjusting means; And an automatic distortion correcting means for automatically correcting the distortion of the reflected image by detecting the distortion. 7. The automatic focus adjusting means includes: a distance measuring mechanism for measuring a focal length to a projection surface based on a reflection image of a projected image projected by the image projecting means; and a projection lens according to the focal length. 7. The image display device according to claim 6, further comprising a lens drive mechanism for automatically adjusting. 8. The image display device according to claim 6, wherein said automatic distortion correction means includes a distortion correction mechanism for automatically correcting distortion based on the reflected image captured by said image input means. 9. A light-emitting unit provided in the image projection unit and a light-receiving unit provided in the image input unit, and a light-emitting unit for focus adjustment or a light-receiving unit for focus adjustment provided in the automatic focus adjustment unit The image display device according to any one of claims 6 to 8, which is also used. 10. The apparatus according to claim 6, wherein said image input means, automatic focus adjustment means, and automatic distortion correction means include start control means which starts in conjunction with the start of projection by said image projection means. Image display device. 11. The image display device according to claim 10, wherein said activation control means is capable of activating said image input means, automatic focus adjustment means and automatic distortion correction means at predetermined intervals. 12. The image display device according to claim 10, wherein said activation control means can activate said image input means, automatic focus adjustment means and automatic distortion correction means at an arbitrary timing. 13. An image signal input device for capturing an image signal, an image processing device for converting the captured image signal into a projection image, an image projection device for enlarging and projecting the projection image toward a projection surface, Automatic focus adjustment means for automatically adjusting the focus of the projected image by measuring the distance to the projection plane, manual distortion correction means for manually correcting the distortion of the projected image, and that the manual distortion correction means has been operated. An image display device, comprising: an operation detecting means for detecting; and an operation control means for performing a focus adjustment by the automatic focus adjusting means when an operation of the manual distortion correcting means is detected by the operation detecting means. 14. An image signal input unit for capturing an image signal, an image processing unit for converting the captured image signal into a projection image, an image projection unit for enlarging and projecting the projection image toward a projection surface, Manual focus adjusting means for manually adjusting the focus of the projected image, manual distortion correcting means for manually correcting the distortion of the projected image, operation detecting means for detecting that the manual distortion correcting means has been operated, An image display device comprising: an operation instructing unit that instructs to perform focus adjustment by the manual focus adjustment when the operation detecting unit detects that the manual distortion correction unit has been operated.