JP4645455B2 - Image projection apparatus, projection image correction method, and program - Google Patents

Description

  The present invention relates to an image projection apparatus, a projection image correction method, and a program.

  In the projector, if the optical axis is not perpendicular to the screen surface, the image projected on the screen is distorted. Therefore, the projector needs to perform trapezoidal correction that corrects the distortion of the image.

  2. Description of the Related Art In recent years, as a projector as an image projection apparatus, a single-plate type projector that performs RGB color expression with a color wheel has become widespread (see, for example, Patent Document 1). This single-plate projector rotates a color wheel on which a plurality of color filters are arranged, time-divides the color, and projects a time-divided color image on a screen. Such projectors are small portable models that are mainly used in home theaters and offices at home.

  Further, in such a projector, the projection image is distorted depending on the projection angle on the screen. Therefore, adjustment operations such as adjustment of the projection angle and keystone correction are required at the time of use. In a conventional projector, such an adjustment is performed by displaying an adjustment image.

JP 2004-72570 A (page 8-10, FIG. 1)

  However, small projectors used in homes and the like are often not carried in a fixed place but carried around. For this reason, every time the projector is moved and used, it is necessary to project an adjustment image to perform the adjustment work, and the adjustment work becomes complicated.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide an image projection apparatus, a projection image correction method, and a computer capable of easily performing adjustment for projecting an image. And

In order to achieve this object, an image projection apparatus according to a first aspect of the present invention includes:
A projection unit that projects a plurality of color images time-divided for different colors onto a projection plane;
A photographing unit for photographing a projection image projected on the projection plane;
A control unit that sets the shooting timing and controls the shooting unit so as to shoot the projection image projected on the projection plane for each different color;
Obtaining a difference image by obtaining a difference between a plurality of captured images of different colors obtained by photographing of the photographing unit, and obtaining a contour line of the projection image from the generated difference image;
A correction unit that acquires the inclination of the outline of the projection image acquired by the outline acquisition unit and corrects distortion of the projection image based on the acquired inclination of the outline. To do.

The projection unit
An image output unit that sequentially supplies a plurality of color images formed based on a plurality of time-division color signals supplied with the color-separated light;
A plurality of color filters corresponding to the plurality of color signals, a color wheel for color-separating light from a light source and supplying the color output to the image output unit;
A rotation control unit that is supplied with a timing signal and controls rotation of the color wheel at a rotation speed based on the supplied timing signal;
A rotation detector that detects rotation of the color wheel and outputs a detection signal;
Each time the rotation detection unit outputs the detection signal, the timing signal is supplied to the rotation control unit, and the video signal is time-divided into a plurality of color signals. Based on the detection signal, the color wheel A time-division drive unit that synchronizes with the color of light supplied to the image output unit and supplies the time-division color signal to the image output unit.

  The control unit acquires a detection signal output from the rotation detection unit, and sets the shooting timing for each different color based on the acquired detection signal and arrangement information of a plurality of color filters of the color wheel. You may do it.

  The control unit may set the photographing timing for each different color based on the number of rotations of the color wheel and the number of color changes.

  The control unit controls the photographing unit so as to photograph the projection image at a first photographing interval capable of discriminating the color of the projection image projected on the projection plane, and the photographing obtained by the first photographing is performed. Every time a photograph is taken with reference to an image, a difference value from the first photographed image is obtained, an extreme value of the obtained difference value is obtained, a time between the obtained extreme value and the extreme value, a photographing time, and the first time The shooting timing may be set for each different color based on one shooting interval.

With a camera
The photographing unit and the control unit may be provided in the camera.

The projection unit includes a zoom mechanism unit,
The control unit determines whether or not the projection image is within an angle of view based on a captured image obtained by imaging of the imaging unit, and when the projection image is out of the angle of view, the projection image is You may make it control the zoom mechanism part of the said projection part so that it may fall within an angle of view.

  The control unit may display a guide indicating a direction in which the projection image falls within the angle of view when the projection image deviates from the angle of view.

The projected image correction method according to the second aspect of the present invention includes:
Projecting a plurality of color images time-divided for different colors onto a projection plane;
Setting shooting timing and shooting the projected image projected on the projection plane for each different color;
Obtaining a difference image by obtaining a difference between a plurality of photographed images of different colors obtained by the photographing, and acquiring a contour line of the projection image from the generated difference image;
Acquiring the inclination of the contour line of the acquired projection image, and correcting distortion of the projection image based on the acquired inclination of the contour line.

The program according to the third aspect of the present invention is:
On the computer,
Projecting multiple color images time-divided for different colors onto the projection surface,
A procedure for setting the shooting timing and shooting the projected image projected on the projection plane for each different color;
A procedure for obtaining a difference image by obtaining a difference between a plurality of photographed images of different colors obtained by the photographing, and acquiring a contour line of the projection image from the generated difference image;
A procedure for acquiring the inclination of the contour line of the acquired projection image and correcting distortion of the projection image based on the acquired inclination of the contour line;
Is to execute.

  According to the present invention, adjustment for projecting an image can be easily performed.

Hereinafter, an image projection apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, an image projection system including a computer will be described.
(Embodiment 1)
FIG. 1 shows the configuration of the image projection system according to the first embodiment.
The image projection system according to the first embodiment includes a computer 1 and a projector 2. The computer 1 and the projector 2 are connected via a USB (Universal Serial Bus) cable 3.

  The computer 1 creates and stores data such as graphs and tables to be projected on the screen S.

  The projector 2 projects an image on the screen S, and a projection lens 112 and a photographing lens 21a are arranged on the front panel. The screen S is raised on the wall W as shown in FIG. As shown in FIG. 2A, the projector 2 takes an image so that the screen S is within the angle of view α of the taking lens 21a, and obtains a projection image Gr projected on the screen S.

  As shown in FIG. 2B, there is a parallax δ between the projection lens 112 and the photographing lens 21a. When the optical axis c1 of the projector 2 is inclined with respect to the vertical axis c2 of the screen S, as shown in FIG. 2A, when the screen S is viewed from the front (in the direction of the vertical axis c2), a projected image is displayed. Is distorted. Even in such a case, the projector 2 is configured to correct the distortion of the projected image.

  As shown in FIG. 3, the projector 2 includes a projection unit 11, a photographing unit 12, and a data processing unit 13.

  The projection unit 11 projects an image based on image data supplied from the data processing unit 13 or RGB signals supplied from the outside. As shown in FIG. 4, the projection unit 11 includes a spatial light modulator 101, a light source lamp 102, a reflector 103, a mirror tunnel 104, a color wheel 105, a color wheel motor 106, and a color wheel control unit 107. , An optical sensor 108, a video input device 109, a time-division drive circuit 110, a light source lens 111, and a projection lens 112.

  The spatial light modulator 101 is composed of a plurality of micromirrors (not shown). Each micromirror is made of, for example, an aluminum piece having a thickness of about 10 to 20 μm, and reflects received light. The spatial light modulator 101 is formed by arranging the micromirror elements in the matrix direction, and is driven and controlled by the time-division drive circuit 110 to tilt each micromirror to emit light emitted from the color wheel 105. Are sequentially projected onto the screen S as a plurality of color images.

The light source lamp 102 emits white light.
The reflector 103 reflects light emitted from the light source lamp 102 toward the mirror tunnel 104.

  The mirror tunnel 104 is for guiding the white light to the color wheel 105 while making the light distribution uniform by reflecting the white light emitted from the light source lamp 102 on the inner surface.

  The color wheel 105 is provided with a plurality of filters for color separation into RGB colors as primary colors of the projected light.

  As shown in FIG. 5, the color wheel 105 has a disk shape, and four filters 105R, 105G, 105B, and 105W are arranged in the circumferential direction. Filters 105R, 105G, and 105B are primary colors (components) that separate the projected light into three primary colors of red (R; Red), green (G; Green), and blue (B; Blue). It is a filter.

  The filter 105W is for adjusting the luminance, and allows the light emitted from the mirror tunnel 104 to pass through as it is. The filters 105R, 105G, 105B, and 105W all have an angle of 90 ° with respect to the center of the color wheel 105, and are evenly arranged.

  The light emitted from the mirror tunnel 104 is irradiated to each of the filters 105R, 105G, 105B, and 105W as a light spot. The areas of the filters 105R, 105G, 105B, and 105W are wider than the light spot. As the color wheel 105 rotates, red, green, blue, and white light is emitted from the color wheel 105 in a time-sharing manner. The

  The color wheel 105 is provided with a hole 105a. The hole 105a is for determining the position of each filter 105R, 105G, 105B, 105W.

  The color wheel 105 rotates to project light from the light source lamp 102 onto each filter.

  Then, the color wheel 105 sequentially supplies the decomposed RGBW light to the spatial light modulator 101. The color wheel motor 106 is for rotating the color wheel 105.

  The color wheel control unit 107 controls the rotation of the color wheel 105 via the color wheel motor 106. The color wheel control unit 107 is supplied with a timing signal from the time division drive circuit 110. The color wheel control unit 107 controls the rotation of the color wheel 105 by rotating the color wheel motor 106 at a constant rotational speed in accordance with the supplied timing signal.

  The optical sensor 108 is configured by a photocoupler, detects rotation of the color wheel 105 by detecting light passing through a hole 105a provided in the color wheel 105, and outputs a light detection signal for each cycle. Output to the time division drive circuit 110.

  The video input device 109 inputs RGB signals of a projection image supplied from the computer 1 and includes a video RAM (not shown). Further, when image data is supplied from the CPU 36, the video input device 109 temporarily stores the RGB signals of the supplied image data in the video RAM.

  The time division drive circuit 110 performs an operation on the RGB signal input to the video input device 109 to generate a luminance signal, and time-divides the RGB signal and the generated luminance signal.

  The time division drive circuit 110 supplies a timing signal to the color wheel control unit 107 every time a light detection signal is supplied from the light sensor 108.

  In addition, since the arrangement of the filters 105R, 105G, 105B, and 105W in the color wheel 105 is known as shown in FIG. 5, the time division drive circuit 110 has a timing at which a light detection signal is supplied from the light sensor 108. Based on the filter 105R, 105G, 105B, 105W, the filter irradiated with the light spot is determined.

  Then, the time division drive circuit 110 synchronizes the irradiation timings to the filters 105R, 105G, 105B, and 105W and the time-divided signals based on the determined filter information, and spatially modulates the time-divided signals. Supply to the vessel 101. Then, the time division driving circuit 110 drives and controls the spatial light modulator 101.

  The light source lens 111 is for condensing the light emitted from the color wheel 105 on the spatial light modulator 101.

The projection lens 112 is for forming an image of the light projected by the spatial light modulator 101 on the screen S, and is disposed on the front panel of the projector 2 as shown in FIGS.
In this manner, the projection unit 11 projects a plurality of color images time-divided for different colors onto the screen S.

  The photographing unit 12 photographs a projected image Gr as shown in FIG. 2A projected on the screen S, and includes a photographing lens device 21 and an image sensor 22.

  The photographing lens device 21 is for photographing the projection image Gr, and includes a photographing lens 21a as shown in FIGS. The photographing lens 21a is provided on the front panel of the projector 2 and condenses light. The photographing lens device 21 includes a peripheral circuit (not shown) for adjusting camera setting parameters such as focus, exposure, and white balance, in addition to the photographing lens 21a.

  The image sensor 22 captures an image formed by the photographic lens device 21 condensing light and acquires digitized image data, and is configured by a CCD (Charge Coupled Device) or the like. Is done.

  The photographing unit 12 can perform high-resolution image photographing and low-resolution image photographing. Low-resolution image capturing is, for example, image capturing with an image resolution of about XGA (1024 × 768 dots), and is capable of reading an image at a speed of 30 fps (frames / second) although the resolution is low. Suitable for movie shooting.

  The high-resolution image capturing is image capturing performed with the maximum number of pixels of the image sensor 22. For example, when the maximum number of pixels of the image sensor 22 is 4 million pixels, the image capturing unit 12 performs image capturing with the maximum number of pixels of 4 million pixels in this high-resolution image capturing.

  The imaging unit 12 configured as described above is controlled by the CPU 36 to perform projection fixed setting imaging of the projection image Gr. That is, the imaging unit 12 captures the projection image Gr at each timing when the light spots are applied to the filters 105R and 105B of the color wheel 105, and acquires a blue projection image and a red projection image.

  The data processing unit 13 includes an interface unit 31, a memory 32, an image processing device 33, an operation unit 34, a program code storage device 35, and a CPU 36.

  The interface unit 31 inputs and outputs data and the like with the computer 1 via the USB cable 3.

  The memory 32 is for temporarily storing image data, and includes a processed image storage area 32a, a work data storage area 32b, and a threshold storage area 32c, as shown in FIG.

  The processed image storage area 32a is an area for storing image data used by the image processing apparatus 33 for image processing. The work data storage area 32b is an area for the CPU 36 to store data necessary for work. The threshold storage area 32c is an area for storing a threshold and the like.

  The image processing device 33 performs image processing on the image data. As the image processing, the image processing device 33 acquires the contour of the projection image, and corrects the projection image based on the acquired contour.

  The image processing device 33 executes contour acquisition processing in order to acquire the contour of the projection image. First, the image processing device 33 generates a difference image d between the blue projection image and the red projection image acquired by the imaging unit 12.

例えば、撮影部１２が、それぞれ、図７（ａ）に示す青の投影画像Gr_Bと図７（ｂ）に示す赤の投影画像Gr_Rとを取得した場合に、投影画像Gr_Bと投影画像Gr_Rとを比較すると、４番目の棒グラフ、スクリーンＳ、壁Ｗの部分等の画像では、差が生じない。 The image processing device 33 generates a difference image d based on the following equation (1).

For example, when the photographing unit 12 acquires the blue projection image Gr_B shown in FIG. 7A and the red projection image Gr_R shown in FIG. 7B, the projection image Gr_B and the projection image Gr_R are obtained. In comparison, there is no difference in the fourth bar graph, the image of the screen S, the wall W, and the like.

  In this case, the image processing apparatus 33 generates a difference image d as shown in FIG. 7C by expressing a region with a difference in a bright gray scale and a region without a difference in a dark gray scale.

  When the white balance of the photographing unit 12 is auto, the image is different between red and blue in the background area so as to be centered. In order to avoid this, it is necessary to set the shooting setting to manual and perform shooting with the same setting.

  Then, the image processing device 33 generates a binary edge image Ge as shown in FIG. 8 based on the difference image d.

  In order to create the binary edge image Ge, for example, a filter for edge detection called a Roberts filter is used. The Roberts filter is a filter that detects the edge of an image by weighting two 4-neighboring pixels to obtain two filters Δ1 and Δ2 and averaging them.

次に、画像処理装置３３は、このようにして得られたエッジ画像を２値化する。画像処理装置３３は、画素値ｅ(x,y）を予め設定された閾値e_thと比較することにより、エッジ画像の２値化を行う。 When the Roberts filter is applied to the pixel value f (x, y) of the pixel at a certain coordinate (x, y), the converted pixel value e (x, y) is expressed by the following equation (2).

Next, the image processing device 33 binarizes the edge image obtained in this way. The image processing device 33 binarizes the edge image by comparing the pixel value e (x, y) with a preset threshold value e_th.

画像処理装置３３は、投影画像の輪郭を取得するため、生成したエッジ２値画像に対して、ハフ変換を行い、投影画像の輪郭線を検出する。 The threshold value e_th may be a fixed value or a variable value obtained by a method such as a variable threshold method, and is stored in advance in the threshold storage area 32c of the memory 32. The image processing device 33 uses the pixel value e (x, y) of the edge image obtained based on Equation 2 to calculate the pixel value f (x, y) at the coordinate (x, y) of the edge binary image using Equation 3. y) is obtained.

In order to acquire the contour of the projection image, the image processing device 33 performs Hough transform on the generated edge binary image and detects the contour line of the projection image.

The Hough transform is a point that forms a straight line on the XY plane as shown in FIG. 9A on the ρ-θ plane as shown in FIG. This is a conversion method for voting and converting the number of votes on the ρ-θ plane.

  When the angle θ is changed from 0 to 360 ° in the coordinates (x, y) of each point, the same straight line is represented by one point on the ρ-θ plane. For this reason, the ρ-θ coordinate having a large number of votes can be determined as a straight line. At this time, since the number of votes is the number of pixels on the straight line, it can be regarded as the length of the straight line. Therefore, the ρ-θ coordinate with an extremely small number of votes represents a short straight line and is excluded from the straight line candidates.

  In the method using the Hough transform, the processing speed decreases as the point to be investigated and the angle θ increases, so it is preferable to reduce the image until the accuracy of the detectable angle is obtained. For this reason, a reduced image is used as an image used for rectangle acquisition. As a result, the number of survey targets can be reduced.

Further, the investigation angle can be reduced by the following method.
Considering the coordinate system with the image center as the origin in the edge image to be investigated, ρ also takes a negative value. Therefore, if the angle θ is measured in the range of 0 ° ≦ θ <180 °, ρ is The remaining 180 ° ≦ θ <0 ° is negative.

However, when the center of the shooting target is located near the center of the image, each side of the shooting target (rectangle) that is actually shot exists vertically and horizontally. In this case, it is more efficient to measure the number of votes on the ρ-θ plane in the range represented by the following formula 9 than to investigate in the range of 0 ° ≦ θ <180 °.

  Moreover, it is possible to specify the upper and lower sides or the left and right sides of the side depending on whether the value of ρ is a positive value or a negative value. Therefore, when the center of the photographing target is located in the vicinity of the center of the image, it is possible to more efficiently select the sides constituting the contour.

  Further, when instructed by the CPU 36 to correct the projection image, the image processing device 33 performs keystone correction based on the inclination of the contour line of the acquired captured image. Then, the image processing device 33 generates a projection image in which the aspect ratio and the angle are correctly corrected as if the screen S was viewed from the front. The image processing device 33 stores the image processed in this way in the processed image storage area 32 a of the memory 32.

  Returning to FIG. 3, the operation unit 34 includes a switch for controlling the projector 2 such as a power switch of the projector 2, a key, a photographing button, and the like. When the user presses these keys and switches, the operation unit 34 responds and transmits this operation information to the CPU 36.

  The program code storage device 35 is for storing a program executed by the CPU 36, and is constituted by a ROM or the like.

  The CPU 36 controls the entire system according to a program stored in the program code storage device 35.

Specifically, the CPU 36 executes the projection image correction process (1).
In the projection image correction process (1), the CPU 36 first initializes correction parameters. The correction parameters are parameters necessary for image effect processing, such as parameters used for trapezoidal correction, maximum value, minimum value, peak value of luminance histogram, peak value, average value of color difference histogram, and the like. The CPU 36 initializes these correction parameters to values in a state where the projection image is not corrected.

  The CPU 36 has a counter and initializes the count value Count of the counter. The counter counts the number of executions of the contour acquisition process of the image processing device 33 when the contour line of the projection image cannot be detected. The CPU 36 stores the count value Count of this counter in the work data storage area 32b of the memory 32. When such initialization is performed, the CPU 36 controls the projection unit 11 to start the projection process.

  When the projection unit 11 starts the projection process, the CPU 36 sets the shooting timing, and controls the shooting unit 12 to shoot a projection image at the set shooting timing. The CPU 36 acquires a light detection signal output from the optical sensor 108 of the projection unit 11 in order to set the photographing timing.

  The CPU 36 determines one cycle of the color wheel 105 based on the output timing of the light detection signal output from the optical sensor 108. As described above, the color wheel control unit 107 drives the color wheel motor 106 to rotate at a constant rotational speed, and the arrangement of the filters of the color wheel 105 does not change.

  For this reason, the CPU 36 can determine the number of rotations of the color wheel 105 and can determine the position of each filter of the color wheel 105 irradiated with the light spot.

  The CPU 36 acquires the output timing of the light detection signal of the optical sensor 108 and the arrangement information of each filter of the color wheel 105 as color wheel information, and for each different color of the color wheel 105 based on the acquired color wheel information. Set the shooting timing. In the first embodiment, the imaging timing is set to the timing at which the light spot is applied to the filter 105B (blue) and the filter 105R (red).

  The CPU 36 controls the photographing unit 12 to perform the projection fixed setting photographing at the set photographing timing. Since there is a shooting time lag, the CPU 36 sets the shooting timing including this time lag. Then, the CPU 36 stores the image obtained by the projection fixed setting shooting in the processed image storage area 32 a of the memory 32.

  When such an image is obtained, the CPU 36 instructs the image processing device 33 to execute a contour acquisition process. Then, the CPU 36 determines whether or not the contour line of the projection image has been detected based on the result of the image processing device 33 executing the contour acquisition process. The CPU 36 makes this determination based on, for example, the number of votes when the image processing apparatus 33 performs Hough conversion.

  That is, a threshold is set in advance for the number of votes, and if the number of votes exceeds this threshold, the CPU 36 determines that the contour line has been detected. The memory 32 stores this threshold value in the threshold value storage area 32c in advance.

  When it is determined that the contour line has been detected, the CPU 36 instructs the image processing device 33 to correct the projection image based on the detected contour line. After the image processing device 33 corrects the projected image, the CPU 36 extracts the corrected image data from the processed image storage area 32 a of the memory 32 and supplies it to the video input device 109 of the projection unit 11.

  On the other hand, when the contour line cannot be detected, the CPU 36 controls the photographing unit 12 to perform the projection fixed setting photographing again. However, there are cases where the projection image cannot be obtained no matter how many times the projection fixed setting shooting is performed, and therefore the CPU 36 sets an upper limit value for the number of executions of the correction of the projection image.

  When the number of executions exceeds the upper limit value, the CPU 36 ends the projection correction process. Specifically, every time the count value Count of the counter is incremented, the CPU 36 compares the incremented count value Count with the upper limit value CountMax.

  The upper limit value CountMax is for limiting the number of times the projection correction process is executed, and the memory 32 stores the upper limit value CountMax in the threshold value storage area 32c in advance. The CPU 36 stores the count value Count in the work data storage area 32b of the memory 32 every time the count value Count of the counter is incremented.

  When the count value Count of the counter exceeds the upper limit value CountMax, the CPU 36 determines that a projection image cannot be obtained, and ends this correction projection processing.

Next, the operation of the image projection system according to the first embodiment will be described.
When the user turns on the power of the projector 2, the CPU 36 reads out the program code from the program code storage device 35 and executes projection correction processing. The CPU 36 executes this projection image correction process (1) according to the flowchart shown in FIG.

The CPU 36 initializes the correction parameter and the counter count value Count (step S11).
The CPU 36 controls the projection unit 11 to start projection processing according to the initialized parameters (step S12).

  The CPU 36 performs a shooting process after the projection unit 11 starts the projection process (step S13).

  The CPU 36 executes the photographing process (1) according to the flowchart shown in FIG.

  The CPU 36 acquires the output timing of the light detection signal of the optical sensor 108 of the projection unit 11 and the color arrangement of each filter of the color wheel 105 as color wheel information (step S21).

  Based on the acquired color wheel information, the CPU 36 determines whether or not it is a projection image capturing timing (step S22). When it is determined that it is not the photographing timing (No in Step S22), the CPU 36 acquires the color wheel information again (Step S21).

  When it is determined that it is the photographing timing (Yes in Step S22), the CPU 36 controls the photographing unit 12 to perform the projection fixed setting photographing of the projected image (Step S23).

  Next, the CPU 36 acquires color wheel information (step S24). Based on the acquired color wheel information, the CPU 36 determines whether it is the timing for shooting another projection image (step S25).

  When it is determined that it is not the photographing timing (No in step S25), the CPU 36 acquires the color wheel information again (step S24).

  When it is determined that it is the photographing timing (Yes in Step S25), the CPU 36 performs the projection fixed setting photographing of the projected image (Step S26).

  As described above, when executing the photographing process (1), the CPU 36 instructs the image processing apparatus 33 to execute the contour acquisition process (step S14 in FIG. 10).

The image processing device 33 executes contour acquisition processing according to the flowchart shown in FIG.
The image processing device 33 performs a calculation according to Equation 1 and generates a difference image d (step S31).

The image processing device 33 performs calculations according to Equations 2 and 3 to create an edge binary image (step S32).
The image processing device 33 performs Hough transform using Equation 4 in order to detect the contour line (step S33).

  The image processing apparatus 33 performs the calculation shown in Equation 4 in the range shown in Equation 5, and uses a plurality of coordinates with a large number of votes as candidates for contour lines forming upper and lower sides, with ρ being + and −, respectively. Are obtained (step S34).

  The image processing device 33 selects ρ and θ having the largest number of votes in the top, bottom, left, and right as the longest, and calculates the angle and the distance of the side from the center (step S35).

  When the image processing device 33 executes the contour acquisition process in this way, the CPU 36 determines whether or not the contour line of the projection image has been detected (step S15 in FIG. 10). When it determines with having detected (Yes in step S15), CPU36 instruct | indicates to correct | amend a projection image with respect to the image processing apparatus 33 (step S16).

  On the other hand, when it is determined that the outline has not been detected (No in step S15), the CPU 36 increments the count value Count of the counter stored in the work data storage area 32b of the memory 32 (step S17).

  The CPU 36 compares the count value Count with the upper limit value CountMax stored in the threshold value storage area 32c of the memory 32, and determines whether or not the count value Count exceeds the upper limit value CountMax (step S18).

  When it is determined that the count value Count does not exceed the upper limit value CountMax (No in step S18), the CPU 36 executes the imaging process and the contour acquisition process again (steps S13 and S14).

  When it is determined that the count value Count has exceeded the upper limit value CountMax without detecting the contour line (Yes in step S18), the CPU 36 ends the projection image correction process (1).

  As described above, according to the first embodiment, the CPU 36 sets the projection timing, the image processing device 33 generates the difference image d between the projection image Gr_R and the projection image Gr_G, and the contour line of the projection image To get. The image processing device 33 corrects the projection image based on the acquired contour line.

  Therefore, the projection image can be corrected without displaying the adjustment image, and the adjustment can be facilitated. For this reason, even for a small model that is easy to carry, particularly used in home theaters and offices at home, adjustment work is easy for beginners.

  Further, by performing this correction processing at regular intervals, even when the projector 2 is moved after the start of correction projection, correction corresponding to the change can be performed without projecting the correction pattern.

  Further, the CPU 36 acquires color wheel information on the output timing of the light detection signal of the optical sensor 108 of the projection unit 11 and the color arrangement of each filter of the color wheel 105, and based on the acquired color wheel information, the projection image Gr_R. , Gr_B shooting timing was set. Therefore, the time-divided projection images Gr_R and Gr_B can be determined inside the projector 2.

(Embodiment 2)
The image projection system according to the second embodiment includes a projector and a camera. The camera projects an image projected on a screen so that a corrected image is projected at the viewer's position.

FIG. 13 shows the configuration of the image projection system according to the second embodiment.
The image projection system according to the second embodiment includes a camera 4 separately from the projector 2. The camera 4 is for photographing a projection image projected on the screen S, and the photographing position is arbitrarily set.

  As shown in FIG. 14, the camera 4 includes a photographing unit 41 and a data processing unit 42. The photographing unit 41 includes a photographing lens device 51 and an image sensor 52 as in the configuration of the first embodiment illustrated in FIG. The photographing lens device 51 and the image sensor 52 are the same as the photographing lens device 21 and the image sensor 22 of the first embodiment, respectively.

  The data processing unit 42 includes an interface unit 61, a memory 62, an image processing device 63, an operation unit 64, a program code storage device 65, and a CPU 66.

  These are the same as the interface unit 31, the memory 32, the image processing device 33, the operation unit 34, the program code storage device 35, and the CPU 36 shown in FIG. The interface unit 61 of the camera 4 and the interface unit 31 of the projector 2 are connected via the USB cable 3.

  When the camera 4 captures a projection image, the color wheel information cannot be used unless the light detection signal is supplied from the light sensor 108 of the projection unit 11 from the projector 2. A differential image cannot be obtained.

  However, even if the color wheel information cannot be used, if the camera 4 can discriminate between the number of rotations of the color wheel 105 and the number of color changes in one turn, the shooting interval is set and shooting is performed at a specific shooting timing. By doing so, an image as shown in FIGS. 7A and 7B can be obtained.

  In the second embodiment, the CPU 36 of the projector 2 supplies information on the number of color changes and the number of rotations in one turn of the color wheel 105 to the camera 4 via the USB cable 3. Then, the CPU 66 of the camera 4 sets the shooting interval wait based on the supplied information.

Next, the operation of the image projection system according to the second embodiment will be described.
The CPU 36 of the projector 2 supplies the camera 4 with information on the number of color changes and the number of rotations in one turn of the color wheel 105.

  Similarly to the first embodiment, the CPU 66 of the camera 4 executes the projection image correction process (1) according to the flowchart shown in FIG.

After starting the projection process (step S12 in FIG. 10), the CPU 66 executes the photographing process (2) according to the flowchart shown in FIG.
The CPU 66 sets a photographing interval based on the supplied information on the number of color changes and the number of rotations in one turn of the color wheel 105 (step S41).

The CPU 66 controls the photographing lens device 51 so as to perform the projection fixed setting photographing (step S42).
The CPU 66 waits for the photographing interval wait (step S43).

  The CPU 66 performs projection fixed setting shooting (step S44), and ends the shooting process (2).

  As described above, when the shooting process (2) is executed, the CPU 66 instructs the image processing apparatus 63 to execute the contour acquisition process (step S14 in FIG. 10). When the CPU 66 determines that the contour line has been detected before the number of executions of the projection correction process exceeds the upper limit value CountMax (Yes in step S15), the CPU 66 obtains the image processing device 63 by photographing with the camera 4. Instructed to perform correction projection based on the captured image (step S16).

  As described above, according to the second embodiment, the projector 2 includes the camera 4 and the camera 4 captures a projection image projected on the screen S. Further, the CPU 66 obtains information on the number of rotations of the color wheel 105 and the number of color changes in one cycle from the projector 2, and sets the photographing timing for each different color. Therefore, the camera 4 can be installed at the viewer's position to check the inclination state of the outline of the projected image, and the viewer can correct the projected image as if viewed from the front.

(Embodiment 3)
In the image projection system according to the third embodiment, when the color wheel information is not used, color wheel calibration is performed so that an imaging interval is obtained so as to obtain an optimal difference image that maximizes the color change. It is.

The image projection system according to the third embodiment has the same configuration as that of the second embodiment. The CPU 66 operates according to the system clock CLK.
In the third embodiment, as a result of continuous shooting by the shooting unit 41 of the camera 4, color wheel calibration processing is performed based on acquired captured images.

  That is, the photographing unit 41 of the camera 4 performs continuous photographing with a high-speed shutter having a short interval compared to one period of the color of the color wheel 105. This shooting interval is defined as a first shooting interval. In this case, since the captured image is not for generating a corrected image, the capturing unit 41 performs continuous capturing with low-resolution image capturing.

  The image processing device 63 obtains the difference d (x, y) according to Equation 1 between the first captured image g (0) and the next captured image g (1), where n is the image number of the captured image. . In order to make it easy to compare the differences, the image processing device 63 adds the differences d (x.y) for all the pixels of one captured image, and acquires the added difference accumulated value k (1).

  Similarly, the image processing device 63 acquires a cumulative difference value k (2) between the first captured image g (0) and the second captured image g (2). In this way, the image processing device 63 sequentially acquires the difference accumulated value k (n).

  When each difference accumulation value k (n) becomes a value as shown in FIG. 16, the CPU 66 compares the difference accumulation values k (1) and k (2).

  In this case, the difference accumulated value k (s-1) in the captured images g (s-1), g (s), g (s + 1) of the image numbers n = (s-1), s, (s + 1). ), K (s), and k (s + 1) are compared, the difference accumulated value k (s) at the system clock timing CLK_s becomes a local minimum value in this vicinity. The CPU 66 stores the system clock timing CLK_s at the time when the difference accumulated value k (n) becomes the minimum value in the work data storage area of the memory 62 as a synchronization point.

  Further, the difference accumulated value k (p-1) in the captured images g (p-1), g (p), g (p + 1) of the image numbers n = (p-1), p, (p + 1). , K (p), k (p + 1), the difference accumulated value k (p) at the system clock timing CLK_p becomes a local maximum value in this vicinity. The interval between the system clock timings CLK_s and CLK_p is an imaging interval at which an optimal difference image is obtained. This shooting interval is set as a second shooting interval.

この同期点からの時間をこの撮影間隔waitで割り算して得られた時間を次の撮影タイミングとして、この撮影タイミングにて次の撮影を行えば、色変化が最大になる差分画像ｄが得られる。ＣＰＵ６６は、このようにして、色変化が最大になる差分画像ｄを取得する。 Actually, since it is necessary to consider not only the interval between the system clock timings CLK_s and CLK_p but also the imaging time, the CPU 66 acquires the imaging interval wait according to the following equation (6).

Using the time obtained by dividing the time from the synchronization point by the photographing interval wait as the next photographing timing, if the next photographing is performed at this photographing timing, a difference image d having the maximum color change can be obtained. . In this way, the CPU 66 acquires the difference image d that maximizes the color change.

Next, the operation of the image projection system according to the third embodiment will be described.
The CPU 66 of the camera 4 executes the projection image correction process (2) according to the flowchart of FIG.
The CPU 66 initializes correction parameters (step S51).
The CPU 66 executes color wheel calibration processing (step S52).

The CPU 66 executes color wheel calibration processing according to the flowcharts shown in FIGS.
The CPU 66 performs continuous shooting with a high-speed shutter (step S61).
The CPU 66 sets 1 to the image number n (step S62).

The CPU 66 obtains a difference d (x, y) of each pixel between the captured image g (1) of the image number n = 1 and the captured image g (n) of the image number n according to the equation 1, and further calculates the difference. The cumulative value k (n) is calculated (step S63).
The CPU 66 increments the image number n (Step S64).

  The image processing device 63 calculates the difference d (x, y) of each pixel between the captured image g (0) and the captured image g (n) according to Equation 1, and further calculates the difference accumulated value k (n). (Step S65).

  The CPU 66 compares the difference accumulation value k (n-1) with the difference accumulation value k (n) to determine whether or not the difference accumulation value k (n) is less than the difference accumulation value k (n-1). Determination is made (step S66).

  When it is determined that the difference accumulated value k (n) is equal to or greater than the difference accumulated value k (n−1) (No in step S66), the CPU 66 increments the image number n, and the captured image g (0) and the captured image g ( The difference accumulated value k (n) with respect to n) is calculated (steps S64 and S65). Then, the CPU 66 compares the difference accumulated value k (n−1) with the difference accumulated value k (n) to determine whether or not the difference accumulated value k (n) is less than the difference accumulated value k (n−1). Determination is made (step S66).

  When it is determined that the difference accumulated value k (n) is less than the difference accumulated value k (n−1) (Yes in Step S66), the CPU 66 increments the image number n (Step S67).

The image processing device 63 calculates the difference d (x, y) of each pixel between the captured image g (0) and the captured image g (n) according to Equation 1, and further calculates the difference accumulated value k (n). (Step S68).
The CPU 66 determines whether or not the accumulated difference value k (n) exceeds the accumulated difference value k (n−1) (step S69).

  When it is determined that the difference accumulated value k (n) is less than the difference accumulated value k (n−1) (No in step S69), the CPU 66 increments the image number n, and the photographed image g (0) and the photographed image g ( The difference accumulated value k (n) with respect to n) is calculated (steps S67, S68). Then, the CPU 66 compares the difference accumulated value k (n−1) with the difference accumulated value k (n), and determines whether or not the difference accumulated value k (n) exceeds the difference accumulated value k (n−1). Determination is made (step S69).

  When it is determined that the difference accumulated value k (n) exceeds the difference accumulated value k (n-1) (Yes in step S69), the CPU 66 uses the time when the captured image g (n) is acquired as a synchronization point, 62 (step S70).

The CPU 66 stores the synchronization point image number n as s (step S71).
The CPU 66 increments the image number n (step S72).
The image processing device 63 calculates the difference d (x, y) of each pixel between the captured image g (0) and the captured image g (n) according to Equation 1, and further calculates the difference accumulated value k (n). (Step S73).

  The CPU 66 compares the difference accumulated value k (n-1) with the difference accumulated value k (n) and determines whether or not the difference accumulated value k (n) is less than the difference accumulated value k (n-1). (Step S74).

  When it is determined that the difference accumulated value k (n) is equal to or greater than the difference accumulated value k (n−1) (No in step S74), the CPU 66 increments the image number n, and the image processing device 63 takes the image according to the equation 1. A difference d (x, y) of each pixel between the image g (0) and the captured image g (n) is obtained, and a difference accumulated value k (n) is further calculated (steps S72 and S73).

  When it is determined that the difference accumulated value k (n) is less than the difference accumulated value k (n−1) (Yes in Step S74), the CPU 66 calculates the shooting interval wait according to Equation 6 (Step S75). Then, the CPU 66 ends the color wheel calibration process.

Next, the CPU 66 executes a photographing process (3) (step S53 in FIG. 17). The CPU 66 executes this photographing process (3) according to the flowchart shown in FIG.
First, the CPU 66 controls the photographing unit 41 to perform the projection fixed setting photographing at the synchronization point (step S81).
The CPU 66 waits for the photographing interval wait (step S82).

The CPU 66 controls the photographing unit 41 to perform the projection fixed setting photographing (step S83).
The CPU 66 shoots with a setting value that can shoot an image of the same color that is visible to the human eye (step S84).

Next, the CPU 66 transmits the image data obtained by photographing to the projector 2 via the interface unit 61 (step S54 in FIG. 17).
The CPU 36 of the projector 2 receives this image data via the USB cable 3 and the interface unit 31 (step S55).

The CPU 36 instructs the image processing device 33 to execute the contour acquisition process (FIG. 12) (step S56).
The CPU 36 instructs the image processing device 33 to correct the projection image (step S57).

  As described above, according to the third embodiment, the camera 4 continuously captures, calculates the difference accumulated value k (n) between the captured images, and obtains the extreme value of the difference accumulated value k (n). As a result, the shooting interval wait is acquired.

  Therefore, it is possible to calculate the shooting interval at which the color change is maximized without using the color wheel information, and to set the shooting timing for each different color by searching for the shooting interval at which the projected image is the clearest. it can.

  Further, by performing the front-facing correction according to the acquired projection area, it is possible to project the front-corrected image without requiring a special projection.

(Embodiment 4)
The image projection system according to Embodiment 4 can perform zoom control.

The image projection system according to the fourth embodiment has the configuration shown in FIG. The projection unit 11 has a zoom mechanism unit (not shown).
The CPU 36 controls the zoom mechanism unit of the projection unit 11 so that the projection image Gr falls within the angle of view α based on the photographed image obtained by the photographing of the photographing unit 12.

Next, the operation of the image projection system according to the fourth embodiment will be described.
The CPU 36 executes the projection image correction process (3) according to the flowchart of FIG.
The CPU 36 initializes correction parameters (step S91) and executes a color wheel calibration process (FIG. 18) (step S92).

The CPU 36 executes the photographing process (3) (FIG. 20) (step S93).
The CPU 36 executes contour acquisition processing (FIG. 12) (step S94).
The CPU 36 determines whether or not the contour of the projection image is within the angle of view α (step S95).

  If it is determined that the contour of the projected image is within the angle of view α (Yes in step S95), an enlargeable amount is calculated (step S96).

The CPU 36 determines whether enlargement is possible (step S97).
When it is determined that enlargement is possible (Yes in step S97), the CPU 36 controls the zoom mechanism unit of the projection unit 11 so as to enlarge the enlargement amount in the tele direction (step S98), and again performs the imaging process (3). (FIG. 20) is executed (step S93).

  When it is determined that enlargement is impossible (No in step S97), the CPU 36 instructs the image apparatus to correct the captured image (step S99), and ends the projection image correction process (3).

  On the other hand, if it is determined that the contour does not fall within the angle of view α (Yes in step S95), the CPU 36 calculates a reduction amount (step S100).

The CPU 36 determines whether or not it falls within the angle of view α (step S101).
If it is determined that the angle falls within the angle of view α (Yes in step S101), the CPU 36 controls the zoom mechanism of the projection unit 11 so as to reduce the reduction amount in the width direction (step S102), and again performs the imaging process. (3) (FIG. 20) is executed.

  When it is determined that the image does not fall within the angle of view α (No in step S101), the CPU 36 instructs the image processing device 63 to correct the captured image (step S99), and this projection image correction process (3 ).

  As described above, according to the fourth embodiment, the CPU 36 performs zoom control so that the projection image Gr falls within the angle of view α, and thus acquires the difference image d having a size corresponding to the angle of view α. And an optimal projection image can be corrected.

(Embodiment 5)
In the image projection system according to the fifth embodiment, when the projection image does not fall within the angle of view, a guide display indicating that fact is performed.

  The image projection system according to the fifth embodiment has the configuration shown in FIG.

  As shown in FIG. 22A, when the projected image Gr deviates from the angle of view α, as shown in FIG. 22B, all the contour lines of the projected image Gr cannot be acquired, and correct correction of the projected image is performed. It becomes impossible to do. In this case, as shown in FIG. 22C, the CPU 36 displays a guide Gd indicating the direction in which the projection image Gr falls within the angle of view α.

Next, the operation of the image projection system according to the fifth embodiment will be described.
The CPU 36 executes the projection image correction process (4) according to the flowchart shown in FIG.

  First, the CPU 36 initializes correction parameters (step S111), and executes a color wheel calibration process (FIGS. 18 and 19) (step S112).

The CPU 36 executes the photographing process (2) (FIG. 15) (step S113).
The CPU 36 executes contour acquisition processing (FIG. 12) (step S114).

  The CPU 36 determines whether or not there is a side protruding from the angle of view α (step S115).

  If it is determined that there is no side protruding from the angle of view α (No in step S115), the CPU 36 instructs the image processing device 63 to correct the captured image (step S116).

  On the other hand, when it is determined that there is a side protruding from the angle of view α (Yes in step S115), the CPU 36 displays a guide Gd instructing that there is a side protruding (step S117).

  If the guide Gd as shown in FIG. 22C is displayed, the viewer can determine that the direction in which the projection image falls within the angle of view α is the left direction. The viewer adjusts the position and angle of the projection unit 11 of the projector 2 in this direction, and the CPU 36 executes the imaging process (2) (step S113) and the contour acquisition process (step S114) again. Becomes within the angle of view α, all the contour lines of the projection image Gr can be acquired.

  As described above, according to the fifth embodiment, when there is a side protruding from the angle of view α, the CPU 36 displays the guide Gd indicating the direction in which the projection image Gr is within the angle of view α.

  Therefore, the CPU 36 can instruct the viewer in an easy-to-understand direction in which the projection image Gr deviates from the angle of view α. Therefore, if the position and angle of the projection unit 11 are adjusted according to this display, the CPU 36 can acquire all the contour lines of the projection image Gr by executing the imaging process (2) and the contour acquisition process again. Thus, correct correction of the projection image Gr can be performed.

In carrying out the present invention, various forms are conceivable and the present invention is not limited to the above embodiment.
For example, in each of the above embodiments, the imaging timing is set to the timing at which the light spot is applied to the filter 105B (blue) and the filter 105R (red). However, the imaging timing may include the timing at which the light spot is applied to the filter 105G (green).

  In the second and third embodiments, the camera 4 is not necessarily used, and the second and third embodiments are applied without using the color wheel information when the projector 2 executes the projection image correction process (2). can do.

  In this case, since it is not necessary to use the color wheel information, the projector 2 does not necessarily have to be a single-plate type as long as it projects images of each color in a time division manner. It doesn't have to be. In the fourth and fifth embodiments, the camera 4 may be provided as in the second and third embodiments.

  In the above embodiments, the computer 1 and the projector 2 are described as being connected via the USB cable 3. However, it may be connected via a wireless LAN or the like. Similarly, the camera 4 and the projector 2 in the second embodiment may be connected via a wireless LAN or the like.

  Further, the computer 1 can be omitted by storing image data such as graphs and tables in the projector 2.

  In each of the above embodiments, the program has been described as being stored in advance in a memory such as a program code storage device. However, a program for operating the photographing apparatus as all or a part of the apparatus or executing the above-described processing is a flexible disk, a CD-ROM (Compact Disk Read-Only Memory), a DVD (Digital Versatile Disk). It may be stored in a computer-readable recording medium such as MO (Magneto Optical disk) and distributed, installed in another computer, operated as the above-mentioned means, or the above-mentioned steps may be executed.

  Furthermore, the program may be stored in a disk device or the like included in a server device on the Internet, and may be downloaded onto a computer by being superimposed on a carrier wave, for example.

It is a figure which shows the structure of the image projection system which concerns on Embodiment 1 of this invention. It is a figure which shows the positional relationship of the projector and screen shown in FIG. 1, and the projection image by this positional relationship. It is a block diagram which shows the structure of the projector shown in FIG. It is a figure which shows the structure of the projection part shown in FIG. It is a figure which shows the color wheel shown in FIG. FIG. 4 is a diagram showing a storage area of the memory shown in FIG. 3. It is a figure which shows the process which acquires a difference image. It is a figure which shows the binary edge image of a projection image. It is a figure which shows the Hough transformation which the image processing apparatus shown in FIG. 3 performs. It is a flowchart which shows the projection image correction process (1) which the projector shown in FIG. 1 performs. It is a flowchart which shows the imaging | photography process (1) which CPU shown in FIG. 3 performs. It is a flowchart which shows the outline acquisition process of the projection image which an image processing apparatus performs. It is a figure which shows the structure of the image projection system which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure of the camera shown in FIG. It is a flowchart which shows the imaging | photography process (2) which CPU shown in FIG. 14 performs. It is a figure which shows the processing content of Embodiment 3 of this invention. It is a flowchart which shows the content of the projection image correction process (2) which CPU of the projector shown in FIG. 3 and CPU of the camera shown in FIG. 14 perform. It is a flowchart which shows the color wheel calibration process (the 1) which CPU of a camera performs. It is a flowchart which shows the color wheel calibration process (the 2) which CPU of a camera performs. It is a flowchart which shows the imaging | photography process (3) which CPU of the camera of a projector performs. It is a flowchart which shows the projection image correction process (3) which CPU of the projector which concerns on Embodiment 4 of this invention performs. It is a figure which shows the processing content of Embodiment 5 of this invention. It is a flowchart which shows the projection image correction process (4) which CPU of a projector performs.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Computer, 2 ... Projector, 4 ... Camera, 11 ... Projection part, 12, 41 ... Shooting part, 33, 63 ... Image processing apparatus, 36, 66 ... CPU

Claims (10)

A projection unit that projects a plurality of color images time-divided for different colors onto a projection plane;
A photographing unit for photographing a projection image projected on the projection plane;
A control unit that sets the shooting timing and controls the shooting unit so as to shoot the projection image projected on the projection plane for each different color;
Obtaining a difference image by obtaining a difference between a plurality of captured images of different colors obtained by photographing of the photographing unit, and obtaining a contour line of the projection image from the generated difference image;
A correction unit that acquires the inclination of the contour line of the projection image acquired by the contour line acquisition unit and corrects the distortion of the projection image based on the acquired inclination of the contour line;
An image projection apparatus characterized by that. The projection unit
An image output unit that sequentially supplies a plurality of color images formed based on a plurality of time-division color signals supplied with the color-separated light;
A plurality of color filters corresponding to the plurality of color signals, a color wheel for color-separating light from a light source and supplying the color output to the image output unit;
A rotation control unit that is supplied with a timing signal and controls rotation of the color wheel at a rotation speed based on the supplied timing signal;
A rotation detector that detects rotation of the color wheel and outputs a detection signal;
Each time the rotation detection unit outputs the detection signal, the timing signal is supplied to the rotation control unit, and the video signal is time-divided into a plurality of color signals. Based on the detection signal, the color wheel A time-division driving unit that synchronizes with the color of light supplied to the image output unit and supplies the time-divided color signal to the image output unit,
The image projection apparatus according to claim 1. The control unit acquires a detection signal output from the rotation detection unit, and sets the shooting timing for each different color based on the acquired detection signal and arrangement information of a plurality of color filters of the color wheel. ,
The image projection apparatus according to claim 2, wherein: The control unit sets the photographing timing for each different color based on the number of rotations of the color wheel and the number of color changes.
The image projection apparatus according to claim 2, wherein: The control unit controls the photographing unit so as to photograph the projection image at a first photographing interval capable of discriminating the color of the projection image projected on the projection plane, and the photographing obtained by the first photographing is performed. Every time a photograph is taken with reference to an image, a difference value from the first photographed image is obtained, an extreme value of the obtained difference value is obtained, a time between the obtained extreme value and the extreme value, a photographing time, and the first time Setting the shooting timing for each different color based on one shooting interval;
The image projection apparatus according to claim 1. With a camera
The photographing unit and the control unit are provided in the camera.
The image projection apparatus according to claim 4, wherein the image projection apparatus is an image projection apparatus. The projection unit includes a zoom mechanism unit,
The control unit determines whether or not the projection image is within an angle of view based on a captured image obtained by imaging of the imaging unit, and when the projection image is out of the angle of view, the projection image is Controlling the zoom mechanism of the projection unit to be within an angle of view;
The image projection apparatus according to claim 1, wherein the image projection apparatus is an image projection apparatus. The control unit displays a guide indicating a direction in which the projection image falls within the angle of view when the projection image deviates from the angle of view.
The image projection apparatus according to claim 7. Projecting a plurality of color images time-divided for different colors onto a projection plane;
Setting shooting timing and shooting the projected image projected on the projection plane for each different color;
Obtaining a difference image by obtaining a difference between a plurality of photographed images of different colors obtained by the photographing, and acquiring a contour line of the projection image from the generated difference image;
Obtaining the inclination of the contour line of the acquired projection image, and performing distortion correction of the projection image based on the acquired inclination of the contour line, and
The projected image correction method characterized by the above-mentioned. On the computer,
Projecting multiple color images time-divided for different colors onto the projection surface,
A procedure for setting the shooting timing and shooting the projected image projected on the projection plane for each different color;
A procedure for obtaining a difference image by obtaining a difference between a plurality of photographed images of different colors obtained by the photographing, and acquiring a contour line of the projection image from the generated difference image;
A procedure for acquiring the inclination of the contour line of the acquired projection image and correcting distortion of the projection image based on the acquired inclination of the contour line;
A program for running

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