JP2011252972A - Projection device, projection method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely prevent flickers due to an image signal processing while considering cost performance.SOLUTION: The projection device comprises an input unit 11 for inputting image signals, a projection system 12 to 26 for generating a light image based on the inputted image signals and projecting this light image, a projection image processing unit 12 for determining whether contents of the image signals are for a static image or for a dynamic image depending on changes of the inputted image signals, a flip image memory 31 for storing the image signals that are determined as the static image, an image processing unit 32 for processing the image signals stored on the flip image memory 31, and a CPU 27 for reading the processed image signals from the flip image memory 31 while the inputted image signals are being determined as the static image, and projecting the read image signals instead of the image signals inputted on the input unit 11.

Description

  The present invention relates to a projection device, a projection method, and a program suitable for projecting a document image such as a form.

  Many projectors have been devised to prevent flickering of a projected image caused by AC driving of a light source lamp. (For example, Patent Documents 1 and 2)

JP 2009-031798 A JP 2009-193044 A

  In addition to the flickering at the light source lamp, depending on the video signal input to the projector, the projected image itself may be partially blurred to cause flickering.

  This partial flickering of the image is caused by an error in the Y (luminance signal) / C (color difference signal) separation process performed on the analog video signal input to the projector, and the analog video signal is A / D converted. This is due to errors in the process, and is often used for general presentations, such as tables, figures, graphs with character strings, etc. The images are projected out of position and flickering as afterimages to the human eye.

  As means for avoiding such a situation, it is conceivable to use a three-dimensional YC separation circuit or a highly accurate A / D conversion circuit. However, these circuits are structurally effective for displaying and projecting still images, but have a disadvantage that they are not cost effective, such as being hardly effective for moving images with fast movement.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a projection apparatus that can reliably prevent flickering caused by processing of an image signal while considering cost efficiency. Another object is to provide a projection method and a program.

  According to the first aspect of the present invention, there is provided an input means for inputting an image signal, a projection means for forming and projecting an optical image based on the image signal input by the input means, and an image signal input by the input means. A discriminating unit that discriminates whether the content of the image signal is a still image or a moving image by a change, a storage unit that stores an image signal that is discriminated as a still image by the discriminating unit, and a storage unit that stores While determining that the image signal input by the input means is a still image by the processing means for processing the image signal and the determination means, the image signal processed by the processing means is read from the storage means and is read by the input means. Projection control means for projecting by the projection means instead of the input image signal is provided.

  According to a second aspect of the present invention, in the first aspect of the invention, a scaling unit that converts an image size and a projection range of an image signal input by the input unit, and a trapezoidal correction for the image signal input by the input unit. The image processing apparatus further includes at least one of trapezoid correction means to perform, and the processing means processes the image signal stored in the storage means after processing by at least one of the resizing means and the trapezoid correction means.

  According to a third aspect of the invention, in the first or second aspect of the invention, the processing means detects a straight line in the image signal stored in the storage means, and performs a smoothing process on the detected straight line. Features.

  According to a fourth aspect of the present invention, in the invention of the third aspect, the processing means extracts a straight line forming a rectangle and a straight line included in the rectangular region from the detected straight lines, and extracts the straight line. Smoothing processing is performed on the straight line formed.

  The invention according to claim 5 is a projection method in a projection apparatus comprising an input unit for inputting an image signal, and a projection unit for forming and projecting a light image based on the image signal input by the input unit. A determination step of determining whether the content of the image signal is a still image or a moving image based on a change in the image signal input from the input unit, and an image signal determined to be a still image in the determination step An image processed in the processing step while determining that the image signal input in the input unit is a still image by the determination step. A projection control step of reading a signal and causing the projection unit to project instead of an image signal input by the input unit.

  The invention described in claim 6 is executed by a computer built in a projection apparatus including an input unit that inputs an image signal and a projection unit that forms and projects an optical image based on the image signal input from the input unit. A determining unit that determines whether the content of the image signal is a still image or a moving image based on a change in the image signal input from the input unit; and the determining unit is a still image. While determining that the image signal input by the input unit by the determination unit is a still image, a storage unit that stores the image signal determined by the processing unit, a processing unit that processes the image signal stored in the storage unit The image signal processed by the processing means is read out and functioned as a projection control means for projecting by the projection unit instead of the image signal input by the input unit.

  According to the present invention, it is possible to reliably prevent flickering due to processing of an image signal while considering cost efficiency.

1 is a block diagram showing a functional circuit configuration of a data projector according to a first embodiment of the present invention. 6 is a flowchart showing the processing contents executed by the CPU in response to image signal input according to the embodiment. The flowchart which shows the processing content which CPU performs with respect to the image signal input based on the 2nd Embodiment of this invention.

(First embodiment)
A first embodiment in which the present invention is applied to a DLP (Digital Light Processing) (registered trademark) data projector apparatus will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a functional circuit of a data projector device 10 according to the present embodiment.
Reference numeral 11 denotes an input unit. The input unit 11 includes, for example, a pin jack (RCA) type video input terminal, a D-sub 15 type RGB input terminal, an HDMI (High-Definition Multimedia Interface) standard image / audio input terminal, and a USB (Universal Serial Bus). An analog image signal and audio signal from an external device connected by wire are input via a connector, and digitized by performing A / D conversion and other predetermined processing as front-end processing.

  The image signals of various standards input and digitized by the input unit 11 are sent to the projection image processing unit 12 via the system bus SB.

  The projection image processing unit 12 unifies the input image signal into an image signal of a predetermined format suitable for projection, writes the image signal to the display video memory 13 as appropriate, and then writes the written image signal from the video memory 13. Read out and send to the projected image drive unit 14.

  At this time, data such as symbols indicating various operation states for OSD (On Screen Display) is also superimposed on the image signal by the projection image processing unit 12 in the video memory 13 as necessary, and the processed image signal is read out. To the projected image drive unit 14.

  Further, the projection image processing unit 12 holds a part of the input image signal, for example, vertical 8 blocks × horizontal 8 blocks (one block is vertical 8 pixels × horizontal 8 pixels) on the upper left side of the image for one frame. A holding unit is provided inside, and under the control of the CPU 27 to be described later, a correlation value between the content of the image signal of the previous frame held in the holding unit and the content of the same portion stored in the video memory 13 is obtained. By calculating, whether the previous frame and the current frame are the same image depending on whether there is a correlation greater than a certain threshold value, that is, the video signal input from the input unit 11 is substantially a still image. Or a movie.

  The projection image drive unit 14 multiplies a frame rate according to a predetermined format, for example, 60 [frames / second], the number of color component divisions, and the number of display gradations, in accordance with the transmitted image signal. The micromirror element 15 that is a spatial light modulation element (SLM) is driven to display by high-speed time-division driving.

  The micromirror element 15 performs display operation by individually turning on / off each tilt angle of a plurality of micromirrors arranged in an array, for example, XGA (horizontal 1024 pixels × vertical 768 pixels) at high speed. Then, an optical image is formed by the reflected light.

  On the other hand, R, G, B primary color lights are emitted cyclically from the light source unit 16 in a time-sharing manner. The primary color light from the light source unit 16 is totally reflected by the mirror 17 and applied to the micromirror element 15.

  Then, an optical image is formed by the reflected light from the micromirror element 15, and the formed optical image is projected and displayed on a screen (not shown) to be projected via the projection lens unit 18.

  The projection lens unit 18 includes a zoom lens and a focus lens therein, and the projection angle of view and the focus position can be changed by moving each lens.

  The light source unit 16 includes a light emitting diode (hereinafter referred to as “R-LED”) 19 that emits red (R) light, a light emitting diode (hereinafter referred to as “G-LED”) 20 that emits green (G) light, and blue ( B) It has a light emitting diode (hereinafter referred to as “B-LED”) 21 that emits light.

  The red light emitted from the R-LED 19 passes through the dichroic mirror 22, is converted into a light beam having a substantially uniform luminance distribution by the integrator 23, and is then sent to the mirror 18.

  The green light emitted from the G-LED 20 is reflected by the dichroic mirror 24, then reflected by the dichroic mirror 22, and sent to the mirror 17 via the integrator 23.

The blue light emitted from the B-LED 21 is reflected by the mirror 25, passes through the dichroic mirror 24, is then reflected by the dichroic mirror 22, and is sent to the mirror 17 via the integrator 23.
The dichroic mirror 22 transmits red light while reflecting green light and blue light. The dichroic mirror 24 reflects green light while transmitting blue light.

  The projection light drive unit 26 controls the light emission timing of each of the LEDs 19 to 21 of the light source unit 16 and the waveform of the drive signal. The projection light driving unit 26 controls the light emission operations of the LEDs 19 to 21 in accordance with the timing of image data given from the projection image driving unit 14 and the control of the CPU 27 described later.

  The CPU 27 controls all the operations of the above circuits. The CPU 27 is directly connected to the main memory 28 and the program memory 29. The main memory 28 is composed of a DRAM and functions as a work memory for the CPU 27. The program memory 29 is composed of an electrically rewritable nonvolatile memory, and stores an operation program executed by the CPU 27, various fixed data, and the like.

  The CPU 27 reads out the operation program data and the like stored in the program memory 29, develops and stores the operation program data in the main memory 28, and executes the program, thereby controlling the data projector device 10 in an integrated manner. To do.

The CPU 32 executes various projection operations in accordance with key operation signals from the operation / display unit 30.
The operation / display unit 30 includes a key operation unit and an indicator unit provided in the main body of the data projector device 10 and a laser light receiving unit that receives infrared light from a remote controller (not shown) dedicated to the data projector device 10. . The operation / display unit 30 directly outputs to the CPU 27 a key operation signal based on a key operated by a user using a key operation unit of the main body or a remote controller.

  Specifically, the power key, input switch key, focus up / down key, zoom up / down key, menu key, cursor ("↑" "↓") “←” “→”) key, set key, cancel key, keystone correction key, image size adjustment, and the like.

The CPU 27 is further connected to the flip image memory 31, the image processing unit 32, and the sound processing unit 33 via the system bus SB.
The flip image memory 31 stores one frame of an image signal for displaying a still image. The image processing unit 32 performs an image processing process for shaping ruled lines and drawings in the image signal stored in the flip image memory 31 under the control of the CPU 27.

  The sound processing unit 33 includes a sound source circuit such as a PCM sound source, converts the sound data given during the projection operation into an analog signal, drives the speaker unit 34 to emit a loud sound, or generates a beep sound or the like if necessary.

Next, the operation of the above embodiment will be described.
As described above, the projection image processing unit 12 creates an image to be displayed on the micromirror element 15 using the video memory 13, and the projection image driving unit 14 displays the created image on the micromirror element 15. The projection light driving unit 26 drives the LEDs 19 to 21 to emit light according to the display on the element 15.

  The projection image processing unit 12, the video memory 13, the projection image driving unit 14, and the projection light driving unit 26 all operate under the control of the CPU 27. The CPU 27 executes the control process after reading out the operation program, fixed data, and the like stored in the program memory 29 and developing them in the main memory 28 including the processes shown below.

  FIG. 2 is a flowchart showing the processing contents of an image projection operation corresponding to a moving image format image signal (hereinafter referred to as “video signal”) input to the input unit 11. In the process of FIG. 2, when a substantial still image is continuously projected at intervals of a few seconds at the shortest, such as a presentation, for example, “flip mode” is a projection mode that actively reduces flickering of these images. The operation when the necessary processing is executed according to the setting state of the flip mode and the content of the input image signal will be described.

  At the beginning of the process, the CPU 27 inputs a video signal from the input unit 11 (step S101), and executes a front-end process including A / D conversion in units of one frame (step S102).

  The image signal for one frame obtained by digitization is stored in the video memory 13 as an image signal having a necessary size and gradation by the projection image processing unit 12.

  At this time, the CPU 27 determines whether or not the flip mode is set as the projection mode based on the contents of the mode setting register provided in the main memory 28 (step S103).

  If it is determined that the flip mode is not set here, the CPU 27 causes the projection image processing unit 12 to read the image signal stored in the video memory 13 to the projection image driving unit 14 as it is.

  The projection image drive unit 14 drives the micromirror element 15 with this image signal to display an image, and projects the light image by the reflected light from the projection lens unit 18 toward the projection target (step S109). Thus, the processing for the image signal for one frame is completed, and the processing returns to the processing from step S101 to prepare for the operation in the next frame.

  If it is determined in step S103 that the flip mode is set, then the partial content of the image signal of the previous frame held in the projection image processing unit 12 as described above and the time point The projection image processing unit 12 calculates the correlation value with the same part of the image signal stored in the video memory 13 in the above, and whether the previous image and the current frame are the same image or not depending on whether or not there is a correlation more than a certain threshold value. It is determined whether or not the video signal input from the input unit 11 is substantially a still image or a moving image (step S104).

  If it is determined that the contents of both image signals do not match and are not the same image, the flip mode is set, but at that time, the image signal of the moving image is input and the image contents change. In step S109, the projection image processing unit 12 causes the projection image driving unit 14 to read out the image signal stored in the video memory 13 as it is.

  The projection image drive unit 14 drives the micromirror element 15 with this image signal to display an image, and projects the optical image of the reflected light from the projection lens unit 18 toward the projection target. Is completed, and the process returns to step S101 to prepare for the operation in the next frame.

  If it is determined in step S104 that the contents of both image signals match and are the same image contents, then the image signal processed for the flip mode at that time is still stored in the flip image memory 31. It is determined whether it has not been performed (step S105).

  This is to determine whether it is the second frame of the image signal having the same content of the same image or the third frame and thereafter.

  If it is the second frame and it is determined that the image signal processed for the flip mode is not yet stored in the flip image memory 31, the image signal for one frame stored in the video memory 13 is read again and processed. For this purpose, it is stored in the flip image memory 31 (step S106).

  Next, the CPU 27 executes a smoothing process for shaping the ruled lines and graphic parts in the image signal stored in the flip image memory 31 by the image processing unit 32 (step S107).

  Since this smoothing process itself is a well-known technique, a detailed description is omitted. However, a part that seems to be a straight line and a curved line is judged and smoothed, and a pixel part that becomes “jagged” out of an unnaturally continuous line is removed. This is the image processing to be eliminated. As an image processing apparatus for performing such a smoothing process, for example, an apparatus as disclosed in JP-A-2-270470 is known.

  The image signal stored in the processed flip image memory 31 is transferred to the video memory 13 for display (step S108), and the process proceeds to step S109 according to the contents of the video memory 13 to display the image. After performing the projection using the processed image signal, the process returns to step S101.

  Thereafter, while the input of the image signal having the same image content continues, it is determined that the image processing for the image signal has been completed in step S105 through the processes in steps S101 to S104, and the processes in steps S106 and S107 are performed. The process skips to step S108, and the process of storing the image signal already stored in the flip image memory 31 in the video memory 13 and performing projection is repeatedly executed.

  In this way, until the image content changes from the second frame after the image signal having the same image content is input, it is stored in the flip image memory 31 instead of the image signal input to the input / output unit 11. In addition, since the projection using the same image signal after the processing by the smoothing process is continued, the flicker of the image can be surely eliminated.

  As described above in detail, according to the present embodiment, it is not necessary to use a three-dimensional YC separation circuit, a highly accurate A / D conversion circuit, or the like for the input / output unit 11, and image signal processing can be performed while considering cost efficiency. It is possible to reliably prevent the flicker caused by.

(Second Embodiment)
A second embodiment when the present invention is applied to a DLP (registered trademark) data projector apparatus will be described below with reference to the drawings.

  Note that the schematic configuration of the functional circuit of the data projector device 10 ′ according to the present embodiment is basically the same as the contents shown in FIG. 1, and the same parts are denoted by the same reference numerals, Illustration and description are omitted.

Next, the operation of the above embodiment will be described.
As described above, the projection image processing unit 12 creates an image to be displayed on the micromirror element 15 using the video memory 13, and the projection image driving unit 14 displays the created image on the micromirror element 15. The projection light driving unit 26 drives the LEDs 19 to 21 to emit light according to the display on the element 15.

  The projection image processing unit 12, the video memory 13, the projection image driving unit 14, and the projection light driving unit 26 all operate under the control of the CPU 27. The CPU 27 executes the control process after reading out the operation program, fixed data, and the like stored in the program memory 29 and developing them in the main memory 28 including the processes shown below.

  FIG. 3 is a flowchart showing the processing contents of the image projection operation corresponding to the moving image format image signal (hereinafter referred to as “video signal”) input to the input unit 11. In the process of FIG. 2, when a substantial still image is continuously projected at intervals of a few seconds at the shortest, such as a presentation, for example, “flip mode” is a projection mode that actively reduces flickering of these images. The operation when the necessary processing is executed according to the setting state of the flip mode and the content of the input image signal will be described.

  In the present embodiment, it is assumed that an image is projected after performing “scaling processing” and “trapezoid correction processing” on the input image signal.

  Here, the “scaling process” refers to resetting a projection portion after performing an image enlargement / reduction process at an enlargement / reduction ratio arbitrarily set by a user within a predetermined range. It is assumed that both the enlargement / reduction magnification information and the information indicating the range in the image used for projection are held in the main memory 28.

  Also, the “trapezoid correction process” means that an image frame that should originally be projected in a rectangular shape is projected in a trapezoidal shape because the projection optical axis of the projection lens unit 18 and the screen surface to be projected are not orthogonal to each other. In order to correct this, in consideration of the distortion, at least one of the vertical and horizontal directions of the image displayed by the micromirror element 15 is displayed in a state of being distorted in the reverse direction in advance, and is projected on the screen as a result. It refers to a technique for performing image processing for canceling distortion so that an image frame becomes a correct rectangle, and at least one distortion rate (reduction) information in the vertical direction and the horizontal direction is held in the main memory 28. .

  At the beginning of the process, the CPU 27 inputs a video signal from the input unit 11 (step S201), and executes a front-end process including A / D conversion in units of one frame (step S202).

  The image signal for one frame obtained by digitization is stored in the video memory 13 as an image signal having a necessary size and gradation by the projection image processing unit 12.

  For the image signal stored in the video memory 13, the CPU 27 uses the information on the enlargement / reduction magnification held in the main memory 28 and the information indicating the range in the image used for the projection to perform a scaling process by the projection image processing unit 12. And the video memory 13 is updated with the image signal after the execution (step S203).

  Subsequently, for the image signal stored in the video memory 13, the CPU 27 performs trapezoid correction processing by the projection image processing unit 12 using the distortion rate (reduction) information in at least one of the vertical direction and the horizontal direction held in the main memory 28. The video memory 13 is updated with the image signal after the execution (step S204).

  After causing the projection image processing unit 12 to execute scaling processing and trapezoid correction processing on the image signal stored in the video memory 13 in this way, the CPU 27 determines whether or not the flip mode is set as the projection mode. Judgment is made based on the contents of the register for setting (step S205).

  If it is determined that the flip mode is not set here, the CPU 27 causes the projection image processing unit 12 to read the image signal stored in the video memory 13 to the projection image driving unit 14 as it is.

  The projection image drive unit 14 drives the micromirror element 15 with this image signal to display an image, and projects the optical image of the reflected light from the projection lens unit 18 toward the projection target (step S211). Thus, the processing for the image signal for one frame is completed, and the processing returns to the processing from step S201 to prepare for the operation in the next frame.

  If it is determined in step S205 that the flip mode is set, then the partial contents of the image signal of the previous frame held in the projection image processing unit 12 as described above and the time point Whether the projected image processing unit 12 calculates a correlation value with the same portion of the image signal stored in the video memory 13 and whether the previous image and the current frame have a correlation greater than a certain threshold value is the same image. It is determined whether or not the video signal input from the input unit 11 is substantially a still image or a moving image (step S206).

  If it is determined that the contents of both image signals do not match and are not the same image, the flip mode is set, but at that time, the image signal of the moving image is input and the image contents change. In step S211, the projection image processing unit 12 causes the projection image driving unit 14 to read the image signal stored in the video memory 13 as it is.

  The projection image drive unit 14 drives the micromirror element 15 with this image signal to display an image, and projects the optical image of the reflected light from the projection lens unit 18 toward the projection target. Is completed, and the process returns to step S201 to prepare for the operation in the next frame.

  If it is determined in step S206 that the contents of both image signals match and are the same, the image signal processed for the flip mode is still stored in the flip image memory 31 at that time. It is determined whether it has not been performed (step S207).

  This is to determine whether it is the second frame of the image signal having the same content of the same image or the third frame and thereafter.

  If it is determined that the image signal processed for the flip mode is not yet stored in the flip image memory 31, the image processing for one frame stored in the video memory 13 is read again and processed. For this purpose, it is stored in the flip image memory 31 (step S208).

  Next, the CPU 27 causes the image processing unit 32 to execute a smoothing process for shaping the ruled lines and graphic parts in the image signal stored in the flip image memory 31 (step S209).

  Since this smoothing process itself is a well-known technique, a detailed description is omitted. However, a part that seems to be a straight line and a curved line is judged and smoothed, and a pixel part that becomes “jagged” out of an unnaturally continuous line is removed. This is the image processing to be eliminated.

  The image signal stored in the processed flip image memory 31 is transferred and stored in the video memory 13 for display (step S210), and then the process proceeds to step S211 according to the contents of the video memory 13, After executing the projection by the processed image signal, the process returns to step S201 again.

  Thereafter, while the input of the image signal having the same image content continues, it is determined that the image processing for the image signal is completed in step S207 through the processing in steps S201 to S206, and the processing in steps S208 and S209 is performed. The process skips to step S210, and the process of storing the image signal already stored in the flip image memory 31 in the video memory 13 and performing projection is repeatedly executed.

  In this way, until the image content changes from the second frame after the image signal having the same image content is input, it is stored in the flip image memory 31 instead of the image signal input to the input / output unit 11. In addition, since the projection using the same image signal after the processing by the smoothing process is continued, the flicker of the image can be surely eliminated.

  As described above in detail, according to the present embodiment, the scaling processing for converting the image size and the image range of the image signal input from the input / output unit 11 and stored in the video memory 13, and at least the vertical and horizontal directions of the image are performed. By performing the trapezoidal correction process in one direction, it is possible to surely eliminate the flickering in the drawing portion such as ruled lines and figures after processing that are emphasized.

  In the above-described embodiment, if the image signal stored in the flip image memory 31 is a still image, the smoothing process for shaping the ruled lines and graphic parts included in the image signal is executed. However, it is not limited to this method.

  For example, a straight line may be detected from the image signal stored in the flip image memory 31, and the straight line group may be the target of the smoothing process. By doing so, it is possible to perform the smoothing process only on the straight line portion where the flicker is conspicuous.

  Further, for example, a straight line forming a rectangle and a straight line included in the rectangle may be further extracted from the detected straight line group, and smoothing processing may be performed on the extracted straight line group.

  In this way, smoothing processing can be performed more efficiently for a straight line portion where the flicker is more conspicuous in a region that attracts viewer's attention such as graphs and tables frequently used for presentation materials.

  In both the first and second embodiments, the present invention has been described for the case where the present invention is applied to a DLP (registered trademark) data projector apparatus. However, the present invention is not limited to the projection method, light source element, and light of the projector. A display device for forming an image, or a single-plate type / multi-plate type of the display device is not limited, and a projection device that projects an image according to the stored contents after temporarily storing an image signal in a memory, Alternatively, the present invention can be applied to any projection method used for the projection apparatus or any program for operating the projection apparatus.

  In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the functions executed in the above-described embodiments may be combined as appropriate as possible. The above-described embodiment includes various stages, and various inventions can be extracted by an appropriate combination of a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, if the effect is obtained, a configuration from which the constituent requirements are deleted can be extracted as an invention.

  DESCRIPTION OF SYMBOLS 10,10 '... Data projector apparatus, 11 ... Input part, 12 ... Projection image process part, 13 ... Video memory, 14 ... Projection image drive part, 15 ... Micromirror element, 16 ... Light source part, 17 ... Mirror, 18 ... Projection lens unit, 19 ... R-LED, 20 ... G-LED, 21 ... B-LED, 22 ... Dichroic mirror, 23 ... Integrator, 24 ... Dichroic mirror, 25 ... Mirror, 26 ... Projection light drive unit, 27 ... CPU 28 ... main memory, 29 ... program memory, 30 ... operation / display unit, 31 ... flip image memory, 32 ... image processing unit, 33 ... audio processing unit, 34 ... speaker unit, SB ... system bus.

Claims (6)

An input means for inputting an image signal;
Projection means for forming and projecting a light image based on the image signal input by the input means;
Discriminating means for discriminating whether the content of the image signal is a still image or a moving image according to a change in the image signal input by the input means;
Storage means for storing an image signal determined to be a still image by the determination means;
Processing means for processing the image signal stored in the storage means;
While the image signal input by the input unit is determined to be a still image by the determination unit, the image signal processed by the processing unit is read from the storage unit, and the projection is performed instead of the image signal input by the input unit. And a projection control means for projecting by the means. It further comprises at least one of scaling means for converting the image size and projection range of the image signal input by the input means, and trapezoid correction means for correcting trapezoid for the image signal input by the input means,
2. The projection apparatus according to claim 1, wherein the processing means processes an image signal stored in the storage means after processing by at least one of the resizing means and the trapezoidal correction means.   The projection apparatus according to claim 1, wherein the processing unit detects a straight line in the image signal stored in the storage unit, and performs a smoothing process on the detected straight line.   The said processing means extracts the straight line which forms a rectangle among the said detected straight lines, and the straight line contained in this rectangular area, The smoothing process of this extracted straight line is characterized by the above-mentioned. Projection device. A projection method in a projection apparatus comprising an input unit for inputting an image signal and a projection unit for forming and projecting a light image based on the image signal input by the input unit,
A determination step of determining whether the content of the image signal is a still image or a moving image according to a change in the image signal input by the input unit;
A storage step of storing the image signal determined to be a still image in the determination step;
A processing step of processing the image signal stored in the storage step;
While the image signal input at the input unit is determined to be a still image by the determination step, the image signal processed at the processing step is read and projected by the projection unit instead of the image signal input at the input unit. And a projection control step. A program executed by a computer built in a projection apparatus including an input unit that inputs an image signal and a projection unit that forms and projects a light image based on the image signal input by the input unit,
The program
A discriminating means for discriminating whether the content of the image signal is a still image or a moving image based on a change in the image signal input by the input unit
Storage means for storing an image signal determined to be a still image by the determination means;
The processing means for processing the image signal stored in the storage means, and the image signal processed by the processing means is read while the determination means determines that the image signal input at the input unit is a still image, A program for functioning as projection control means for projecting by the projection unit instead of the image signal input by the input unit.

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