JPH09258329A - Illumination irregularity eliminating method for overhead projector with image input function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for eliminating illumination irregularity from an image picked up by an overhead projector with an image input function. SOLUTION: The illumination irregularity on the upper surface of a stage is picked up (first image pickup action) and first image data obtained by the first image pickup action is recorded by a microcomputer. The image and the illumination irregularity of a transmissible original on the stage are picked up (second image pickup action) and second image data obtained by the second image pickup action is recorded by the microcomputer. Then, arithmetic operation for deleting the content of the first image data from the second image data is executed by the microcomputer so as to produce corrected image data obtained by eliminating the illumination irregularity. When the corrected image data is recorded, the clear image can be reutilized afterward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overhead projector having an image input function, and more particularly to a method of removing illumination unevenness from an image of a transparent original image.

[0002]

2. Description of the Related Art An overhead projector capable of displaying a large manuscript when giving a presentation to a large number of people is used. In this overhead projector, for example, a transparent original is placed as a projection target on a stage made of a Fresnel lens or a transparent glass plate, the transparent original is illuminated by a light source through the Fresnel lens, and the illumination light that illuminates the transparent original is illuminated. It is condensed by a projection head arranged above the stage and projected on a screen.

Further, recently, a presentation made by an overhead projector is video-captured, or it is taken into a microcomputer to make a database, which can be reused later.
In order to facilitate the use of such an overhead projector, the transparent original document is projected onto the screen, and an image input function for capturing the content of the transparent original document and inputting it to a video player or a microcomputer is provided. Various overhead projectors provided with this have been proposed.

The above-mentioned overhead projector with an image input function is one for picking up an image of a transparent original projected on a screen, and an illumination light for illuminating the transparent original is split by a half mirror into a projection system and an imaging system. However, these have the drawbacks that the captured image becomes insufficient in light quantity, the color reproducibility is poor, and the captured image becomes very difficult to see when the screen shakes. . Therefore, as an overhead projector with an image input function that solves these drawbacks, an imaging device is provided near the projection head, and a stage, a reflection mirror,
There is one in which the image pickup device itself is moved so that the optical path for projection is guided to the image pickup device, and the transparent original on the stage is directly imaged. According to this, a clear image with good color reproducibility can be obtained.

[0005]

However, when an image is input by the above-mentioned overhead projector, the light emitted from the light source is emitted from the stage, and the emitted light is reflected in the room and is again displayed on the stage. It may be irradiated to. According to this, there is a problem that illumination unevenness occurs in the transparent original on the stage, and the image pickup signal also includes illumination unevenness, resulting in an unclear image. Further, this illumination unevenness becomes more prominent when there is illumination in the room, external light entering the room, and the like, and it is difficult to prevent it as long as image input is performed in the room.

An object of the present invention is to solve the above problems, and it is an object of the present invention to provide a method of removing illumination unevenness from an image picked up by an overhead projector with an image input function.

[0007]

In order to solve the above problems, an illumination unevenness removing method for an overhead projector with an image input function according to claim 1 inputs an image pickup signal from an image pickup device to a microcomputer, and The microcomputer converts the image pickup signal into image data, and the illumination unevenness is removed from the image data by arithmetic processing.

According to another aspect of the overhead projector with an image input function, the first image pickup for picking up the illumination unevenness on the stage where the transparent original is not placed, and the transparent original placed on the stage. The second image pickup for picking up the image described in 1) and the illumination unevenness on the transparent original is performed, and the first image pickup is performed by the microcomputer from the second image data obtained by the second image pickup. The calculation processing for deleting one image data is performed to create the corrected image data from which the uneven illumination is removed.

[0009]

2 shows an example of an overhead projector with an image input function. The overhead projector 2 is composed of a box-shaped housing 3 that serves as a base, a pillar 4 assembled on the back side of the housing 3, and a projection head 5 that is movable along the pillar 4 in the vertical direction. Has been done. Further, wheels 6 that support the overhead projector 2 and are used during movement are provided on the lower surface of the housing 3.

Inside the housing 3, a light source 8, a condenser lens 9 and a stage 10 are arranged from below. The light source 8 includes a lamp 11 and a reflector 12, is held by a bracket 13 and is attached to the bottom surface of the housing 3, and irradiates the light of the lamp 11 upward. The condenser lens 9 is held by the bracket 14 and arranged above the light source 8, and collects the light from the light source 8 and irradiates it to the stage 10. Although not shown, in the vicinity of the light source 8 inside the housing 3,
A cooling fan for cooling the light source 8 and a power supply unit are arranged. A power switch and a slit for introducing outside air into the housing 3 are provided on the outer wall of the front surface or the side surface of the housing 3.

The stage 10 is composed of a transparent glass plate 16 arranged on the upper surface of the housing 3 and two Fresnel lenses 17 and 18 arranged below the glass plate 16. In the overhead projector 2,
On the upper surface of the glass plate 16, a transparent original 20 having an image written on a transparent plastic sheet is placed.
An image of 0 is projected and imaged. A transparent liquid crystal display may be placed on the upper surface of the glass plate 16 instead of the transparent original 20, and an image displayed on the transparent liquid crystal display may be projected and picked up.

The projection head 5 has a mounting portion 22 which is mounted on a column 4 assembled on the back side of the housing 3.
A projection unit 23 arranged above the stage 10 for projecting the image of the transparent original 20 toward the screen, and an arm unit 24 connecting the projection unit 23 and the mounting unit 22.
The image pickup unit 25 is an image pickup device that is arranged above the arm unit 24 and picks up an image of the transparent original 20 on the stage 10.

The mounting portion 22 has a cylindrical shape into which the support column 4 is inserted, and an operation knob 26 used for vertically moving the projection head 5 along the support column 4 is rotatably provided on one side surface thereof. It is assembled. The operation knob 26 is coaxially provided with a pinion gear 27 arranged in the mounting portion 22, and the pinion gear 27 meshes with a rack gear 28 formed on the front side of the column 4. The projection head 5 is movable in the up-down direction by meshing the pinion gear 27 and the rack gear 28 by rotating the operation knob 26.

The projection unit 23 is arranged so as to face the center of the stage 10, and a projection lens 30 that collects illumination light that illuminates the image of the transparent original 20 through the stage 10 and passes through the projection lens 30. The mirror house 33 includes a reflection mirror 32 that reflects the reflected light toward the screen or toward the imaging unit 25, and a mirror house 33 that holds and covers the reflection mirror 32. It is assembled above the projection lens 30 in the assembled state.

The reflection mirror 32 has a mirror holding plate 35.
The mirror holding plate 35 is attached to
As shown in FIG. 5, the mirror house 33 is held by a support shaft 36 attached to one side surface of the mirror house 33. Support shaft 3
6 is a bearing portion 3 formed on the side surface of the mirror house 33.
7 is rotatably inserted in the bearing hole 38, and a screw 39 formed at the tip of the bearing meshes with a screw hole 41 formed on the side surface of the mirror holding plate 35 via a washer 40.
It holds the mirror holding plate 35.

On the other end side of the support shaft 36, an operation knob 4 used for operation when rotating the mirror holding plate 35.
3 are integrally formed. Operation knob 43 and support shaft 36
A screw 44 is provided between the operation knob 43 and the bearing portion 37, and a stopper knob 45 screwed to the screw 44 is disposed between the operation knob 43 and the bearing portion 37. The stopper knob 45 fixes the operation knob 43 and restricts the rotation of the mirror holding plate 35 by bringing the end surface into contact with the bearing portion 37 by utilizing the screw engagement with the screw 44. Note that knurled grooves are formed on the outer peripheral surfaces of the operation knob 43 and the stopper knob 45 in order to prevent slippage during operation.

On the upper side in the projection unit 23, two regulating pins 47 inserted from the outside of the mirror house 33,
48 are arranged. These restriction pins 47, 48
Is for positioning the mirror holding plate 35 at the time of projection and at the time of image pickup. As shown by the two-dot chain line in the figure, the operation knob 4
When 3 is rotated to bring the mirror holding plate 35 into contact with the regulation pin 47, the reflection mirror 32 faces the opening 49 side formed on the front surface side of the mirror house 33, and the projection is made by directing this opening 49 toward the screen. You can do it.
Further, as shown by the solid line in the figure, when the mirror holding plate 35 is brought into contact with the regulation pin 38, the reflection mirror 32 faces the opening 50 formed on the back side and is arranged facing the opening 50. The illumination light is reflected toward the image pickup unit 25.

As described above, the operation knob 43 is operated to bring the mirror holding plate 35 into contact with either of the regulation pins 37 and 38 and fixed by the stopper knob 45, so that the reflection mirror 32 is projected or imaged. Can be easily positioned.

The image pickup section 25 includes an image pickup camera 52 for picking up an image of a projection object placed on the stage 10, and a reflecting mirror 3.
The image pickup lens 53 forms an image of the illumination light emitted from the image pickup device 52 on the image pickup camera 52, and a main body 54 that holds these.

The image pickup camera 52 has a built-in image pickup element such as a CCD, and has an output terminal for photoelectrically converting a picked-up image and outputting it as a video signal (image pickup signal) of the NTSC system or the like. Imaging camera 5 to main body 54
In the assembly of No. 2, the imaging camera 52 is inserted through the opening 54a formed on the back side of the main body 54, and the opening 54a is closed by the back cover 56. The back cover 56 is formed with a hole 56a through which a connection cord 57 connected to the output terminal of the image pickup camera 52 is inserted.

The image pickup lens 53 is held by the lens barrel 62 and is attached to the front side of the main body 54. This lens barrel 6
2, the outer peripheral surface is exposed from the upper surface of the main body 54,
It can be rotated from the outside. Then, when the lens barrel 62 is rotated, the lens barrel 62 advances and retracts along the optical axis direction while holding the imaging lens 53, and focusing can be performed.

A connection cord 57 is attached to the image pickup camera 53.
Is connected to the microcomputer 65.
The microcomputer 65 can input a video signal and converts the input video signal into an image signal and handles it. Further, a floppy disk drive 6 for writing and reading data to and from the floppy disk 66.
A keyboard 68 that has a built-in 7 and is used for operation
And a display 69.

Next, the above-mentioned overhead projector 2
FIG. 1 shows a method for removing illumination unevenness from an image obtained by capturing an image of the transparent original 20 using the microcomputer and the microcomputer 65.
This will be described with reference to FIG.

First, the overhead projector 2 is set in a state in which an image can be input. Loosen the stopper knob 45 shown in FIG. 3, operate the operation knob 43 to bring the mirror holding plate 35 into contact with the regulation pin 48, and tighten the stopper knob 45 again. Thereby, the reflection mirror 32 is arranged so as to face the opening 50 on the back side. Further, since the operation knob 43 is fixed by the stopper knob 45, the reflection mirror 32 does not rotate carelessly during image pickup. Then, the imaging camera 52 and the microcomputer 65 are connected by the connection cord 57.

After the overhead projector 2 is set in a state in which an image can be input as described above, the upper surface of the stage 10, which is the first imaging, is imaged. When the overhead projector 2 is powered on without the transparent original 20 placed on the stage 10, the lamp 11 of the light source 8 is turned on, and the light emitted from the lamp 11 is condensed by the condenser lens 9, Fresnel lenses 17, 18 and the glass. After passing through the plate 16, it enters the image pickup lens 53 through the projection lens 30 and the reflection mirror 32, and an image is formed on the image pickup camera 52 by the image pickup lens 53.

The image pickup camera 52 photoelectrically converts the incident illumination light into a video signal, which is input to the microcomputer 65 by the connection cord 57. The microcomputer 65 outputs the video signal obtained by imaging the stage 10 as a first video signal.
Since the image data is converted and displayed on the display 69, the height of the projection head 5 and the lens barrel 62 are moved while looking at the display 69 to perform focusing.

If the display 69 is checked and there is no illumination unevenness, the transparent original 20 is imaged as it is. Further, as shown in FIG. 4A, when the illumination unevenness 71 is confirmed on the display 69, the first image data including the illumination unevenness 71 is recorded in the floppy disk 66.

Next, the transparent original 20 is placed on the stage 10, and a second image pickup for picking up an image of the transparent original 20 and uneven illumination of the transparent original 20 is performed. As a result, the microcomputer 65 converts the image of the transparent original 20 and the illumination unevenness into the second image data, so that the image 69 of the transparent original 20 is displayed on the display 69 as shown in FIG. 4B.
And illumination unevenness 74 are displayed. This second image data is also recorded on the floppy disk 66.

The microcomputer 65 is operated to create corrected image data from the second image data and the first image data. To create the corrected image data, the contents of the first image data, that is, the illumination unevenness 74 is deleted from the second image data. Since the illumination unevenness 74 obtained by the second imaging and the illumination unevenness 71 obtained by the first imaging have the same density and the same size because the transparent original 20 is transparent, the transparent original of the second image data is transmitted. The image 20 is not deleted, and only the image 73 of the transparent original 20 is displayed on the display 69. If this corrected image data is recorded on the floppy disk 66, it can be reused later.

In the above embodiment, the video signal is output from the image pickup unit and the video signal is converted into image data by the microcomputer. However, the image pickup unit is provided with a function of converting the video signal into image data. If so, the data conversion in the microcomputer can be omitted. Further, although the illumination unevenness of the transparent original is removed, the illumination unevenness of the display image of the transmissive liquid crystal display can be similarly removed. Further, it is also possible to eliminate the illumination unevenness of the reflective original other than the transparent original. When removing the illumination unevenness of the reflective original, the reflectance of the stage and the reflective original are different, so it is preferable to image the plain reflective original in the first imaging stage.

[0031]

As described above, the illumination unevenness removing method for an overhead projector with an image input function of the present invention inputs an image pickup signal from an image pickup device to a microcomputer, and the microcomputer outputs the image pickup signal to image data. Since the conversion is performed and the illumination unevenness is removed from this image data by the arithmetic processing, the illumination unevenness can be easily and reliably removed, and a clear image can be obtained.

Further, the first image pickup for picking up the stage and the second image pickup for picking up the transparent original are performed, and the first image including only the uneven illumination is obtained from the second image data including the image of the transparent original and the uneven illumination. Since the arithmetic processing for deleting the data is performed, only the uneven illumination can be removed, and the image of the transparent original is not deteriorated.

[Brief description of drawings]

FIG. 1 is a flowchart showing a procedure of an illumination unevenness removing method of the present invention.

FIG. 2 is a cross-sectional view of main parts showing an outline of an overhead projector with an image input function.

FIG. 3 is a main-portion cross-sectional view showing the structure of a projection unit.

FIG. 4 is an explanatory diagram showing display contents of a display corresponding to each stage of uneven illumination removal work.

[Explanation of symbols]

 2 overhead projector 5 projection head 8 light source 10 stage 20 transmissive original document 23 projection unit 25 imaging unit 32 reflection mirror 65 microcomputer

Claims (2)

[Claims] 1. A stage on which a transparent original on which an image is printed is placed, a light source for illuminating the transparent original on the stage through a Fresnel lens, and a transparent original placed above the stage to illuminate the transparent original. An overhead projector with an image input function, comprising: a projection head for projecting illumination light toward a screen; and an image pickup device for picking up an image of a transparent original placed on a stage and inputting the image pickup signal to an external device. An overhead projector with an image input function characterized by inputting an image pickup signal from an image pickup device to a microcomputer, converting the image pickup signal into image data by this microcomputer, and removing illumination unevenness from this image data by arithmetic processing. Method for removing uneven lighting. 2. A first image pickup for imaging illumination unevenness on a stage in which the transparent original is not placed, an image written on the transparent original placed on the stage, and illumination on the transparent original. A second image pickup for picking up unevenness is performed, and the microcomputer performs arithmetic processing for deleting the contents of the first image data obtained by the first image pickup from the second image data obtained by the second image pickup. The correction image data in which the uneven illumination is removed is created.
A method for removing uneven illumination of an overhead projector with an image input function described.