JP2001285691A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type display device with ease of adjustment and excellent cost performance. SOLUTION: The projection type display device is provided with an image pickup section 1 that picks up an image of an object and a projection section 3 that can project an object image picked up by the image pickup section 1 onto a screen 5, and the image pickup section 1 can picks up an image projected on the screen 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device having an image pickup section.

[0002]

2. Description of the Related Art Conventionally, as a material presenting apparatus capable of imaging a material on a stage with an imaging head, reproducing the video image on the spot, and transmitting image information to a large number of viewers simultaneously on a large screen, for example, Japanese Patent Application Laid-Open No. There was one disclosed in JP-A-253182.

The apparatus comprises a housing provided with a stage on which an object is mounted on an upper surface, an imaging head which is installed above the stage by a column, and which images the object on the stage, and converts the image of the imaged object into a video signal. The housing includes a liquid crystal projection mechanism for projecting a subject image picked up by the image pickup head onto a screen outside the housing.

On the other hand, for example, there is a display adjusting device of a projection type display device as disclosed in Japanese Patent Application Laid-Open No. Hei 5-30520.

The apparatus specifies image displayable area information obtained by photographing the entire area of the image displayable area by photographing means as coordinates of four points on a memory means, and obtains a memory to be obtained based on an adjustment image. A first position coordinate on the means is calculated from the coordinates of the four points, and based on a result of comparing the second position coordinate on the memory means specified based on the image for adjustment, the adjustment control means In this publication, the apparatus exemplifies the screen distortion and convergence of the projected image as the objects to be adjusted.

[0006]

However, in the apparatus disclosed in JP-A-6-253182, the imaging head is used only for imaging the subject on the stage.

On the other hand, in the apparatus disclosed in JP-A-5-30520, the photographing means is used only for photographing the projected adjustment image.

As described above, in the conventional apparatus, the imaging of the subject used for the presentation and the imaging of the projection image used for various adjustments are performed by different imaging means. There is a problem that the relative positioning of the projection display device is troublesome.

Further, when the projection type display device is provided with an image pickup means used only for adjustment purposes,
Although the problem of relative positioning is eliminated, there is a problem that it causes a cost increase.

The present invention has been made in view of the above problems, and has as its object to provide a projection display device which is easy to adjust and has excellent cost performance.

[0011]

Means for Solving the Problems To solve the above problems,
The invention according to claim 1 includes an imaging unit that captures an image of a subject, and a projection unit that can project a subject image captured by the imaging unit onto a screen, wherein the imaging unit converts an image projected onto the screen. A projection display device capable of capturing an image.

According to a second aspect of the present invention, there is provided the projection display apparatus according to the first aspect, wherein the image pickup unit is capable of performing a tilt image pickup at least when picking up an image projected on the screen. Is a projection type display device.

According to a third aspect of the present invention, in the projection type display device according to the second aspect, the projection unit is capable of changing a projection tilt amount, and the tilt imaging by the imaging unit is performed by the projection unit. The projection type display device is changed in accordance with the change of the projection tilt amount in the above.

According to a fourth aspect of the present invention, there is provided the projection type display device according to the first aspect, wherein when the imaging area of the imaging section is changed between the subject and the image projected on the screen, The projection type display device is characterized in that a focus state of an imaging lens of the imaging unit is switched.

According to a fifth aspect of the present invention, there is provided the projection type display apparatus according to the fourth aspect, wherein the focus state of the imaging lens at the time of imaging the subject immediately before capturing the projected image projected on the screen. Having a storage unit for storing the focus state stored in the storage unit when the imaging of the image projected on the screen is changed to the imaging of the subject. This is a projection type display device characterized by returning to a focus state.

According to a sixth aspect of the present invention, in the projection type display device according to the fourth aspect, the projection unit has a distance measuring means for measuring a distance between the projection unit and the screen. A projection display apparatus, wherein a focus state of the imaging lens when the imaging unit captures an image projected on the screen is determined based on a distance measured by a distance measuring unit.

According to a seventh aspect of the present invention, there is provided the projection display device according to the first aspect, wherein the same color of the image pickup surface of the image pickup unit is obtained from the resolution corresponding to the same color pixel of the image projected on the screen. The projection type display device is characterized in that the imaging unit has an optically zoomable imaging lens so that a resolution corresponding to a pixel is higher.

According to an eighth aspect of the present invention, in the projection display device according to the first aspect, when the imaging section captures an image projected on the screen, the projection section displays an image of a test pattern. This is a projection type display device that performs projection.

According to a ninth aspect of the present invention, in the projection display device according to the eighth aspect, when the imaging section captures the image of the subject, the projection section displays the subject image captured by the projection section. This is a projection type display device that performs projection.

According to a tenth aspect of the present invention, in the projection display device of the first aspect, the frame period of the image pickup by the image pickup unit is an integral multiple of the frame period of the projection by the projection unit. Is a projection type display device.

According to an eleventh aspect of the present invention, in the projection type display device of the first aspect, the one frame scanning cycle of the image pickup device provided in the image pickup unit is set to one of the image display units provided in the projection unit. A projection type, wherein the timing is set to be longer than a frame scanning period, and the timing at which the imaging unit captures an image projected on the screen is determined by the scanning timing of the imaging element and the scanning timing of the image display unit. A display device.

According to a twelfth aspect of the present invention, there is provided the projection type display device according to the first aspect, wherein the setting of the image pickup unit at the time of imaging the subject immediately before imaging the projected image projected on the screen. A storage unit for storing a state, wherein when the imaging of the image projected on the screen is changed to the imaging of the subject, the setting state stored in the storage unit is read out, and when the imaging of the subject is performed, The projection type display device is characterized by returning to the setting state.

[0023]

FIG. 1 shows a projection display according to an embodiment of the present invention.

The imaging head 1 is fixed to the projection unit 3 by the arm 2, captures an image of a subject placed on the upper part 4 of the projection unit 3, and projects the video image on the screen 5.

Here, the image pickup area of the image pickup head 1 is not limited to the upper part of the projection unit 3, and the object is placed around the projection unit 3 by rotating the arm 2, and the image is taken. It may be. Further, the imaging head 1 is configured to be rotatable with respect to the arm 2, and the rear surface of the projection unit 3 (FIG.
May be configured to be able to capture an image.

In the present embodiment, the imaging head 1
In other words, at least the projection type display device is configured such that the imaging head 1 is mounted on the arm 2 so that an image of a subject used for a presentation can be captured, and a projection image of the projection unit 3 on the screen 5 can be captured. And can be rotated.

The following description will be made using the above configuration. However, unlike the above configuration, the arm 2 is particularly bent so that the imaging head 1 can image the screen 5. Is also good.

By rotating the imaging head 1 with respect to the arm 2 and directing it to the screen 1, the imaging head 1
The test pattern projected on the screen 5 from the projection unit 3 can be imaged. At this time, the projection unit 3 receives a video signal output from the imaging head 1 and corrects convergence, white balance, shading (including color unevenness), trapezoidal distortion, and the like of the projected image.

In general, the projection unit 3 is often placed on a horizontal surface, and a large number of viewers can view a screen image with an image display unit (for example, a liquid crystal panel) inside the projection unit 3. By moving the positional relationship of the projection lens parallel to the screen from its normal position, tilt projection as shown in FIG. 1 is often performed.

Here, since the image pickup position of the image pickup head 1 and the image display unit of the projection unit 3 are spatially distant from each other, the image projected on the screen 5 can be completely read by the image pickup element of the image pickup head 1. In order to capture an image in a region without trapezoidal distortion, it is desirable that the imaging head 1 itself also has a tilting imaging function.

If trapezoidal distortion occurs in the image pickup system, when acquiring various correction data such as shading and color unevenness, the signal processing of the image pickup system performs signal processing of the image pickup system to remove trapezoidal distortion. Since it is necessary to perform the interpolation calculation using, the burden on hardware and software increases.

The above-described correction of the trapezoidal distortion of the projected image is, for example, a correction of the trapezoidal distortion of the projected image of the projection unit 3 having no function of adjusting the amount of tilt of the projected image. An image is taken, image data having trapezoidal distortion is created in advance in the projection unit 3 based on the imaged data, and this image is projected to cancel the trapezoidal distortion of the projected image.

For example, Japanese Patent Application Laid-Open No. 10-229515 discloses an imaging device having a tilting function. FIG. 12 of the publication discloses a projection type display device having an imaging device as an example of a conventional device. It has been disclosed. However, even when the imaging device according to the invention described in the publication is applied to the device described in FIG. 12 of the publication, the imaging device itself is not configured to capture a screen. Can not achieve the purpose.

When the projection unit 3 has a tilt projection function and the relative positional relationship between the image display unit and the projection lens can be changed in a plane parallel to the screen, for example, by a motor or the like, The relative positional relationship between the imaging lens of the imaging head 1 and the imaging device is also determined within a plane parallel to the screen.
For example, if the configuration is changed by a motor or the like in accordance with the change amount of the tilt projection, the imaging area of the imaging element can be made to coincide with the screen 5.

The imaging distance differs between when the screen 5 is imaged and when, for example, an object placed on the upper part 4 of the projection unit 3 is imaged, the focus of the imaging lens may be changed in each case. desirable.

Some projection units 3 have an autofocus function. Therefore, the imaging head 1
However, when the screen 5 is imaged, the focus of the imaging lens included in the imaging head 1 may be changed using the autofocus distance measurement information of the projection lens included in the projection unit 3.

Here, the zoom magnification of the imaging lens of the imaging head 1 will be considered.

In the case of HDTV (High Definition TV),
The detection limit of the time difference between the G, B, and R signals is said to be 3.5 ns.
３７37). This corresponds to about 0.26 pixels.

Therefore, it is desirable that the imaging head 1 can image at least a part of the screen 5 with the above resolution. At this time, a part of the screen 5 is imaged by the zoom function. However, in the case of the electronic zoom, since the data obtained by the interpolation operation is not a true value, it is obviously meaningless. It is.

FIG. 4 shows a case where a liquid crystal panel is used as an image display unit provided in the projection unit 3 and corresponds to a part of pixels constituting one liquid crystal panel of a single color among a plurality of liquid crystal panels. (A1, A2) and a portion (B1) corresponding to a part of pixels of the same color on the imaging surface of the imaging head 1.
To B32) will be described for the case where, for example, a three-chip CCD is used as the imaging head 1.

With such a configuration, A1,
A portion corresponding to a pixel constituting a liquid crystal panel of a color different from the liquid crystal panel of A2 is displayed on the screen, for example, A1-
Even if the pixel interval of A2 is shifted by ４, the imaging head 1 can detect the shift of the convergence in each of the horizontal and vertical directions.

That is, when the test pattern is picked up by the image pickup head 1, convergence detection can be performed using the image pickup head 1 as long as the image can be optically zoomed to the above resolution.

Further, a configuration may be adopted in which a black-and-white camera is used as the imaging head 1 and a color camera is used, and image data of each color is captured in a time-division manner. By doing so, it is possible to substantially eliminate the registration error caused by the imaging head 1 itself, excluding the registration caused by the chromatic aberration of the imaging lens.

On the other hand, when an RGB primary color filter is used for imaging by the imaging head 1, for example, when a single-plate type color CCD camera is used as the imaging head 1, a plurality of liquid crystal panels are used. A portion corresponding to a part of a pixel constituting one liquid crystal panel and a pixel of the same color on an imaging surface of the imaging head 1 (for example, G (green))
R (red) and B (blue), which have fewer pixels on the imaging surface than
It is sufficient that zooming is possible until the relationship of a part corresponding to a part of (pixels) becomes as shown in FIG.

FIG. 3 shows a single plate type color C
When a CD is used, portions A1 to A4 corresponding to some of the pixels constituting the liquid crystal panel, and portions R1 to R9 corresponding to some of the pixels of each color on the imaging surface of the imaging head 1;
It is a figure which shows the example of a relationship with G1-G18 and B1-B9. Although the detection accuracy of the convergence is slightly inferior, the optical zoom may be performed up to the zoom magnification such that the relationship shown in FIG. 3 is established, and the interpolation processing may be performed thereafter.

In FIG. 3, the data of the portion without the captured image of the corresponding color is calculated by interpolation, and
Pixel convergence can be detected.

In the above description, the case where the convergence detection limit is 1/4 pixel and 1/3 pixel has been described. However, the present invention is not particularly limited to this.

The required zoom magnification is determined by the accuracy of convergence detection to be detected.

That is, on the screen 5, at least the same color of the image pickup surface of the image pickup element of the image pickup head 1 on the screen 5, based on the resolution of the portion corresponding to the pixel of the same color of the image display unit in the projection unit 3 on the screen 5. It is sufficient that the optical zoom is enabled by the imaging lens so that the resolution corresponding to the pixel of the above becomes higher.

For example, when convergence is detected at a plurality of points on the screen 5, it is necessary to move the imaging point on the screen 5 of the imaging head 1.

For example, by moving the relative positional relationship between the imaging surface of the imaging device of the imaging head 1 and the imaging lens in a plane parallel to the screen 5, the imaging area on the screen can be moved. .

Apart from this, when shading data of a projected image on the screen 5 is to be obtained, the entire effective projection area of the screen 5 may be imaged, and its spatial frequency characteristics are low. , The above resolution is not required.

FIG. 2 shows a block diagram for realizing this embodiment.

The imaging head 1 captures a subject to be used for a presentation and, at the same time, is configured to rotatably support the imaging head 1 with the arm 2 so that a projection image on the screen 5 can be captured.

The image formed on the image pickup surface of the image pickup device 32 by the image pickup lens 31 is subjected to photoelectric conversion, and is subjected to a signal processing unit 33.
After predetermined signal processing is performed, the signal is input to the J terminal of the switch 34 of the projection unit 3 via the arm 2. To the other input terminal K of the switch 34, a video signal from the outside of the present apparatus is input via a terminal H.

When the image pickup head 1 is oriented in the direction of the screen 5, the control unit 51 detects the state by the switch 47.

The output of the switch 34 is input to the signal processing unit 35, and the output of the signal processing unit 35 is
Input to the terminal. The other input terminal M of the switch 42 includes:
An output of the memory 43 in which image data of some test patterns is stored is input.

The selection terminals of the switches 34 and 42 are controlled by the control unit 51.

The output of the switch 42 is supplied to the LCD drive 36
An LCD (liquid crystal panel, which is an image display unit) 37 is driven by the output of the unit, spatial light modulation is performed using a light source (not shown), and an image is displayed on the screen 5 via a projection lens 38. Is projected to

The light emitting section 39 and the light receiving section 40 are for measuring the distance between the projection section 3 and the screen 5, and the distance is measured using, for example, infrared rays. Here, the distance measurement is not limited to infrared rays, and may be performed using other light, electromagnetic waves, ultrasonic waves, or the like. The focus of the projection lens 38 of the projection unit 3 may be adjusted by a motor 49 described later based on the distance measurement information obtained by the light-emitting unit 39 and the light-receiving unit 40 so as to perform autofocus.

The motor 44 is a motor for controlling the zoom of the image pickup lens 31, and the motor 45 is a motor for controlling the zoom of the image pickup lens 31.
The motor 46 controls the focus of the motor.
For example, it is a motor that moves the imaging lens 31 in a plane parallel to the screen 5 and controls the amount of tilting projection.

The motor 48 is a motor for controlling the zoom of the projection lens 38, the motor 49 is a motor for controlling the focus of the projection lens 38, and the motor 5
Reference numeral 0 denotes a motor that moves the projection lens 38 in a plane parallel to the screen 5 and controls the amount of image pickup.

The memory 41 is a memory for storing the setting state of the projection lens 31.

The operation will be described below.

By the switch 47, the state of the imaging lens 31 immediately before the imaging head 1 captures an image of the screen 5, that is, the zoom and focus of the imaging lens 31 when the imaging head 1 captures an object to be used for a presentation. The amount of tilt image pickup is stored in the memory 41.

At this time, the imaging lens 31 of the imaging head 1 directed to the screen 5 adjusts the imaging tilt amount (controlled by the motor 50) of the projection lens 38 and the imaging tilt amount (based on the distance measurement information). The focus (controlled by the motor 45) and the focus (controlled by the motor 45) are set. For example, when the state of the projection lens 38 is changed, the state of the imaging lens 31 may be changed accordingly.

Thus, the effective projection area on the screen 5 can be imaged by the imaging head 1 without causing trapezoidal distortion.

The interlocking operation of the two lenses 31 and 38 is performed only when the imaging head 1 is facing the screen 5. The detection that the imaging head 1 faces the direction of the screen 5 can be detected by the switch 47, but may be performed by operating means (not shown).

When the imaging head 1 faces the screen 5, a test pattern corresponding to the image data stored in the memory 43 is projected on the screen 5. As the test pattern, for example, a test pattern having a high spatial frequency component (for example, an edge component) is used for obtaining convergence correction data, and a uniform luminance test pattern is used for obtaining color shading / shading correction data. In accordance with the above, for example, it is selected and projected by operating means (not shown).

The irradiation of the test pattern is performed by the imaging head 1
May be automatically detected upon detecting that the screen 5 is facing the direction of the screen 5. This detection can be performed by the switch 47. Specifically, switch 4
7, the direction of the imaging head 1 is changed to the screen 5
, The switch 42 selects the M terminal,
The control unit 51 controls the projection of the test pattern stored in the memory 43.

Here, particularly for obtaining convergence correction data, it may be desirable to obtain correction data at a plurality of points (areas) on the screen 5.

For this reason, the imaging lens 31 is
Thereby, it is possible to move to a plurality of places in a plane parallel to the screen 5. In this case, the imaging lens 31
Of the motor 44 until the resolution described above is obtained.
It is configured to be movable.

The data obtained by imaging the test pattern on the screen 5 by the imaging head 1 is taken into the signal processing unit 35 and the control unit 51, and the correction data is calculated by this. For example, a correction process in the signal processing unit 35 is performed based on

The memory section 41 is provided with the imaging lens 3 in this case.
1 can be stored.

Here, when the imaging head 1 captures an image of a subject other than the screen 5 for use in a presentation, the switch 47 detects this and reads out the setting information stored in the memory 41 to read the previous presentation. Imaging lens 31 when imaging a subject used for
Can be returned to the setting state. This information (zoom, focus, tilt image pickup amount) is stored in the memory 41 as described above. In addition to this information, for example, imaging conditions such as gain, white balance, and negative / positive inversion that are specially set at the time of imaging a subject used for presentation can be stored. Switching from test pattern imaging to subject imaging used for presentation is possible. In this case, it is possible to automatically return to these stored states.

Here, scanning of the imaging head 1 and the projection unit 3 when the imaging head 1 faces the screen 5 and captures a test pattern will be considered.

When acquiring correction data of various characteristics, basically, data for one projection screen only needs to be obtained.

For example, when acquiring shading data, if the scanning of the imaging system is terminated during the scanning of one screen of the projection system, the image data obtained as a result of the imaging will be different depending on the location. The brightness will be different. For this reason, for example, the imaging element 3 of the imaging head 1
In the case where a CCD is used as 2, the frame rate of the imaging system is set lower than the frame rate of the projection system, and the charge accumulation period of the CCD of the imaging head 1 is set only during one effective screen display period of the projection system. , An image may be taken.

In the above description, the case where the data for one projection screen is obtained when acquiring the correction data of various characteristics has been described. However, in order to reduce the influence of noise of the imaging head 1, the data for a plurality of projection screens is obtained. It is desirable to obtain correction data by obtaining data and averaging the data, that is, to calculate the correction data after noise reduction. The noise reduction is performed by the signal processing unit 35. The noise reduction operation may be performed using a CPU (not shown) in the signal processing unit 35, or may be performed using a digital filter.

The frame scanning cycle of the imaging system may be P times (P is an integer) the frame scanning cycle of the projection system. At this time, the charge accumulation time of the image sensor of the imaging system is set to one frame scanning period of the projection system or to Q times (Q is an integer of P or less) of one frame scanning period of the projection system. Good. In this case, it is desirable that the scanning of the imaging system and the scanning of the projection system are synchronized.

Next, correction of trapezoidal distortion of the projection system will be described.

The imaging head 1 captures a projected image having a trapezoidal distortion projected on the screen 5, and inputs a captured video signal to the projection unit 3. The switch 34 selects the J terminal,
The captured video signal is sent to the control unit 51 via the signal processing unit 35.
, And calculates the trapezoidal distortion correction data, and returns the correction data to the signal processing unit 35. Specifically, the signal processing unit 35
Receives the correction data, performs digital processing with different interpolation coefficients in the image area, generates trapezoidal distortion opposite to the projected image on the image data, and projects the image. As a result, trapezoidal distortion of the projection optical system and image data is canceled, and a projection image without distortion can be obtained.

The switching of the imaging direction of the imaging head 1 is desirably controlled by a motor (not shown) in order to ensure reproducibility of imaging. In this case, the control voltage of the same motor in each imaging direction may be stored in the memory 41.

[0084]

As described above, according to the first to twelfth aspects of the present invention, it is also possible to take an image of a test pattern image or the like on a screen by using an imaging unit used for imaging a subject for a presentation. it can. According to this device,
In correspondence with various situations, a projection display device can be installed, and at the same time, an imaging unit used for imaging a test pattern or the like,
It can also be used for imaging a subject used for a presentation.

According to the second and third aspects of the present invention, the imaging unit
When shooting a screen, tilting is possible, so
Imaging of the effective projection area becomes possible. Since the projection area and the imaging area can be matched, it is not necessary to perform an interpolation calculation in consideration of trapezoidal distortion when calculating various correction data.

According to the third aspect of the invention, the projection unit has a function of changing the amount of projection tilt, and the imaging unit is configured to move in conjunction with the screen imaging, thereby improving usability.

According to the fourth, fifth, and sixth aspects of the present invention, when the imaging unit is pointed at the screen, the focus state of the imaging unit switches, so that it is not necessary to perform cumbersome focus setting.

According to the fifth and twelfth aspects of the present invention, since the setting of the previous use state can be stored, it is possible to perform the test pattern imaging and the imaging of the subject to be used for the presentation without performing any troublesome various settings. .

According to the sixth aspect of the present invention, the projection unit has a distance measuring function, and the imaging unit operates the imaging lens at the time of screen imaging by using this information. The distance measuring function can be omitted.

According to the seventh aspect of the present invention, the image pickup unit is optically controlled so that the resolution corresponding to the pixels on the image pickup surface of the image pickup unit is higher than the resolution corresponding to the pixels of the image projected on the screen. Since the imaging lens is provided with a zoomable lens, convergence data can be obtained.

According to the eighth aspect of the present invention, since the projecting section irradiates the test pattern when the imaging section faces the screen, the usability is improved.

According to the tenth aspect of the present invention, since the frame scanning period of the imaging unit is set to an integral multiple of the frame period of the projection unit, stable captured image data can be obtained.

According to the eleventh aspect, the one-frame scanning period of the imaging unit is made longer than the one-frame scanning period of the projection unit. Since the configuration is determined, stable captured image data can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a projection display device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a projection display device according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a relationship between a part corresponding to a part of a pixel constituting an image display unit and a part corresponding to a part of a pixel of each color on an imaging surface of the imaging head 1;

FIG. 4 is a diagram illustrating an example of a relationship between a part corresponding to a part of a pixel constituting an image display unit and a part corresponding to a part of a pixel of each color on an imaging surface of the imaging head 1;

[Explanation of symbols]

1: imaging head, 2: arm, 3: projection unit, 4: upper projection unit, 5: screen, 31: imaging lens, 32: imaging device, 33, 35: signal processing unit, 32, 34, 47: switch, 36: LCD drive unit, 37: LCD (screen display unit), 38: projection lens, 39: light emitting element, 40: light receiving element, 44, 45, 46, 48, 49, 50: motor,
51: control unit.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H04N 5/232 H04N 5/232 EJZ 9/31 9/31 A

Claims (12)

[Claims] An imaging unit configured to image a subject; and a projection unit configured to project a subject image captured by the imaging unit onto a screen, wherein the imaging unit can capture an image projected on the screen. A projection type display device characterized by the following. 2. The projection type display device according to claim 1, wherein the imaging unit is capable of performing tilting imaging at least when capturing an image projected on the screen. apparatus. 3. The projection display device according to claim 2, wherein the projection unit is capable of changing a projection tilt amount, and the tilt imaging by the imaging unit is performed by the projection tilt by the projection unit. A projection type display device which is changed according to a change in the amount. 4. The projection type display device according to claim 1, wherein when the imaging area of the imaging section is changed between the subject and the image projected on the screen, the imaging of the imaging section is performed. A projection display device, wherein a focus state of a lens is switched. 5. The projection display device according to claim 4, wherein a storage state for storing a focus state of the imaging lens at the time of capturing the subject immediately before capturing a projection image projected on the screen. Means for reading out the focus state stored in the storage means when the imaging of the image projected on the screen is changed to imaging of the subject, and returning to the focus state at the time of imaging the subject A projection type display device characterized by being made to work. 6. The projection type display device according to claim 4, wherein the projection unit has a distance measuring unit for measuring a distance between the projection unit and the screen, and the distance is measured by the distance measuring unit. A projection display device, wherein a focus state of the imaging lens when the imaging unit captures an image projected on the screen is determined based on the distance measured. 7. The projection display device according to claim 1, wherein a resolution corresponding to a pixel of the same color on the imaging surface of the imaging unit is higher than a resolution corresponding to a pixel of the same color of the image projected on the screen. The projection type display device, characterized in that the imaging unit has an imaging lens that can be optically zoomed so that the height is higher. 8. The projection display device according to claim 1, wherein when the imaging unit captures an image projected on the screen, the projection unit projects an image of a test pattern. Projection type display device. 9. The projection display device according to claim 8, wherein, when the imaging section images the subject, the projection section projects a subject image captured by the projection section. Projection type display device. 10. The projection type display device according to claim 1, wherein a frame period of the image picked up by the image pickup unit is an integral multiple of a frame period of the image projected by the projection unit. apparatus. 11. The projection type display device according to claim 1, wherein a one-frame scanning cycle of an image sensor included in the imaging unit is longer than a one-frame scanning cycle of an image display unit included in the projection unit. A projection type display device, wherein a timing at which the imaging unit captures an image projected on the screen is determined by a scan timing of the imaging element and a scan timing of the image display unit. 12. The projection display device according to claim 1, wherein a setting state of the imaging unit is stored at the time of capturing the subject immediately before capturing a projection image projected on the screen. Means for reading out the setting state stored in the storage means when the imaging of the image projected on the screen is changed to imaging of the subject, and returning to the setting state at the time of imaging of the subject A projection type display device characterized by being made to work.