JP2005269454A - Photographing apparatus, and photographing processing method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to immediately carry out a photographing after an original is photographed at a high resolution. <P>SOLUTION: A camera 1 for paintings and calligraphy reads a low resolution image after carrying out high resolution photographing and image correction or the like, extracts a low resolution image stored in advance in a memory, and obtains an image change amount being a difference between the extracted low resolution image and the read low resolution image. Further, the camera 1 for paintings and calligraphy stores the read low resolution image to the memory. When the image change amount exceeds a prescribed threshold value, the camera 1 for paintings and calligraphy discriminates whether or not the image makes any motion. Moreover, when the camera 1 for paintings and calligraphy discriminates that the image takes no motion, the camera 1 for paintings and calligraphy reads the low received signal image until the discrimination indicates the presence of a motion. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photographing apparatus, a photographing processing method, and a program.

  In recent years, as a photographing device, a user photographs a document placed on a document table with a camera, stores image data of the document photographed with the camera, performs image processing, and uses a projector to capture an image of the document on a screen. There is what is projected in an enlarged manner (see, for example, Patent Document 1).

Further, as a conventional photographing apparatus, there is an apparatus that monitors the movement of an image and, if there is no movement in the image, sets the resolution of the camera to a high resolution and photographs a document.
JP 2002-354331 A (page 2-3, FIG. 1)

  However, if the camera resolution is set to a high resolution even after the document has been shot, the movement of the image is determined based on the high resolution image. Therefore, if there is a change during the capture of the high resolution image as in the case of replacing the document, it is not possible to immediately take a picture. For example, in high-resolution shooting, since the shooting cycle is about 3 to 5 seconds per frame, it takes about 10 seconds to determine a change in an image when a high-resolution image is acquired and compared three times. End up.

  For this reason, it is conceivable that the image resolution is automatically switched to a low resolution after shooting with the image resolution switched to a high resolution. However, after that, when it is determined that there is no movement in the image again, the operation of switching the image resolution to a high resolution and shooting is repeated.

  Also, if the brightness changes due to the flicker of a fluorescent lamp, it is misrecognized that there is a motion, and even though it is stationary, it erroneously returns to a still image detection waiting state.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a photographing apparatus, a photographing processing method, and a program capable of correctly determining the movement of an image.

In order to achieve this object, an imaging device according to the first aspect of the present invention provides:
A photographing device for photographing a document,
A photographing unit for photographing the original document at a low resolution or a high resolution;
When the original is photographed at a high resolution, the photographing unit is controlled to photograph the original by switching the resolution to a low resolution, and the original is obtained based on the low-resolution image of the original obtained by photographing by the photographing unit. And a controller for determining the presence or absence of the movement.

A storage unit for storing a photographed image obtained by photographing of the photographing unit;
The control unit stores, in the storage unit, data of a low resolution image obtained by the imaging unit capturing the original at a low resolution, and newly captures the original at a low resolution from the low resolution image stored in the storage unit. The difference between the low-resolution image of the read data and the new low-resolution image obtained by shooting by the shooting unit is acquired as an image change amount, and the acquired image change amount is a preset threshold value. It may be determined that the manuscript has moved when the value exceeds.

A storage unit for storing a photographed image obtained by photographing of the photographing unit;
The control unit stores in the storage unit data of a low-resolution image obtained by photographing by the photographing unit before the photographing unit photographs the original at high resolution, and after photographing the original at high resolution. The low-resolution image data stored in the storage unit is read out from the storage unit, and the low-resolution image data newly obtained by the imaging unit is stored in the storage unit. The difference between the resolution image and the new low-resolution image obtained by photographing by the photographing unit is acquired as an image change amount, and it is determined that the document has moved when the acquired image change amount exceeds a preset threshold value. You may make it do.

A storage unit for storing a photographed image obtained by photographing of the photographing unit;
The control unit stores in the storage unit data of a low-resolution image obtained by photographing by the photographing unit before the photographing unit photographs the original at high resolution, and after photographing the original at high resolution. When the photographing unit photographs the original document at a low resolution, the low resolution image data before the high resolution photographing stored in the storage unit is read from the storage unit, and the low resolution image of the read data and the photographing are read out. A difference from a new low-resolution image obtained by photographing a part is acquired as an image change amount, and it is determined that the document has moved when the acquired image change amount exceeds a preset threshold value. Good.

  The control unit acquires an average brightness of a new low-resolution image obtained by shooting of the shooting unit, determines whether or not the acquired average brightness is within a preset specified range, and the average brightness is the If determined to be within the specified range, the average luminance of the low-resolution image of the data read from the storage unit and the average luminance of the new low-resolution image obtained by shooting of the shooting unit match each other. You may make it acquire the said image variation | change_quantity by adjusting each pixel value of a low-resolution image.

  When the average brightness of the new low-resolution image obtained by the photographing by the photographing unit exceeds a preset specified value, the control unit then obtains a new low-resolution image obtained by the photographing by the photographing unit. A resolution image may be acquired, and it may be determined whether the average luminance of the acquired low resolution image is within the specified range.

The imaging processing method according to the second aspect of the present invention is:
A step of shooting a document in high resolution;
Switching the resolution to a low resolution and shooting the document at a low resolution;
Determining whether or not the document is moving based on a low-resolution image of the document obtained by photographing the document at a low resolution.

The program according to the third aspect of the present invention is:
On the computer,
Procedure for shooting a document at high resolution,
A procedure for switching the resolution to a low resolution and shooting the document at a low resolution;
A procedure for determining the presence or absence of movement of the document based on a low-resolution image of the document obtained by photographing the document at a low resolution;
Is to execute.

  According to the present invention, it is possible to correctly determine the movement of an image.

Hereinafter, an imaging device according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, the photographing apparatus will be described as a photographed image projecting apparatus that projects a photographed image.
(Embodiment 1)
FIG. 1 shows the configuration of a captured image projection apparatus according to Embodiment 1 of the present invention.
The captured image projection apparatus includes a document camera 1 and a projector 2.

  The document camera 1 is a camera system for photographing a document 4 to be projected, and includes a camera unit 11, a support column 12, a pedestal (document table) 13, and an operation table 14. The camera unit 11 is for photographing the document 4. A digital camera is used for the camera unit 11. The column 12 is for attaching the camera unit 11. The pedestal 13 is for supporting the column 12 and for placing the document 4. The camera unit 11 captures the document 4 including the pedestal 13. Therefore, the captured image obtained by capturing by the camera unit 11 may or may not include the image of the document 4.

  As shown in FIG. 2, the document camera 1 includes an image data generation unit 21 and a data processing unit 22. The image data generation unit 21 captures the document 4 and captures the image data of the document 4.

  The data processing unit 22 acquires image data of the captured original 4 from the image data generation unit 21, performs image processing, and outputs the image data subjected to the image processing to the projector 2.

  The image data generation unit 21 and the data processing unit 22 may be provided in the camera unit 11 shown in FIG. 1, or the image data generation unit 21 and the data processing unit 22 are respectively connected to the camera unit 11 and the operation console. 14 may be provided.

  The image data generation unit 21 includes an optical lens device 101 and an image sensor 102.

  The optical lens device 101 is composed of a lens that collects light in order to photograph the document 4.

  The image sensor 102 is for capturing an image formed by the optical lens device 101 condensing light as digitized image data, and is configured by a CCD or the like. The image sensor 102 has a function of photographing the document 4 at a low resolution or a high resolution.

  The data processing unit 22 includes a memory 201, a display device 202, an image processing device 203, an operation unit 204, a program code storage device 205, and a CPU 206.

  The memory 201 is for temporarily storing an image from the image sensor 102, image data to be sent to the display device 202, and the like. As shown in FIG. 3, the memory 201 includes an image storage area (high) 201a, an image storage area (low) 201b, and a projection image storage area 201c.

The image storage area (high) 201a is a storage area for storing a high-resolution image. The image storage area (low) 201b is a storage area for storing a low-resolution image. The projection image storage area 201 c is an area for storing a projection image for projection onto the screen 3.
The display device 202 is for displaying an image sent out to the projector 2.

  The image processing device 203 is for performing image correction processing such as image distortion correction and image effect on the image data temporarily stored in the memory 201.

  The image processing device 203 performs distortion correction (trapezoid correction) on the image of the document 4 captured obliquely or rotated with respect to the imaging surface of the camera unit 11, thereby correcting the document 4 captured from the front. Generate an image. Specifically, in order to perform distortion correction, the image processing apparatus 203 cuts a rectangle from the image of the distorted document 4 and performs projective conversion on the image of the document 4 to the cut rectangle to perform inverse conversion.

  The operation unit 204 includes switches, keys, shooting buttons, and the like for controlling the document projection function. The operation unit 204 outputs operation information to the CPU 206 when the user operates these keys and switches.

  The program code storage device 205 is for storing a program executed by the CPU 206, and is configured by a ROM or the like.

  The CPU 206 controls each unit in accordance with a program stored in the program code storage device 205. The memory 201 is also used as a work memory for the CPU 206.

  Further, the CPU 206 determines whether or not there is a motion in the image of the document 4 that is the shooting target, according to a flowchart described later, and switches the shooting mode according to the determination result.

  There are two shooting modes, a moving image mode and a still image mode. The moving image mode is a mode that is set when the user intends to place the document 4 or the like that the user wants to project on the pedestal 13, and is a mode that projects the image projected by the camera unit 11 onto the projector 2 as it is.

  In the moving image mode, for example, the CPU 206 controls each unit so that an image with an image resolution of about VGA (640 × 480 dots) is projected at a speed of 30 fps (frames / second). As described above, the moving image mode is a mode in which real-time characteristics are emphasized although the resolution is low. When the CPU 206 reads the low resolution image in the moving image mode, the CPU 206 stores the read low resolution image in the image storage area (low) 201 b of the memory 201.

  The still image mode is a mode that is set after the user places the document 4, and is a mode in which the camera unit 11 captures a high resolution image and projects a high resolution still image. When the camera unit 11 is a camera with an imaging resolution of 3 million pixels, the cut-out projected image is an XGA (1024 × 768) still image. When the CPU 206 reads a high resolution image in the still image mode, the CPU 206 stores the read high resolution image in the image storage area (high) 201 a of the memory 201.

  The CPU 206 determines whether or not there is a motion in the image of the document 4 in order to switch the shooting mode. In order to make such a determination, the CPU 206 obtains an image change amount MD from the previously captured image. The image change amount MD is an amount representing how much the image being taken has changed compared to the previous image. There are several ways to calculate this quantity. As an example, the CPU 206 obtains the sum of absolute values of differences between pixels as the image change amount MD from the data of the previously captured image.

That is, if the previous pixel data is Pn-1 (x, y), the current pixel data is Pn (x, y), and 1 ≦ x ≦ 640 1 ≦ y ≦ 480, the image change amount MD is the following number: Represented by 1.
However, since the amount of calculation is large in order to obtain the total sum of all the pixels, as a method for obtaining the image change amount MD, there is a method in which several pixels are extracted and realized.

  In addition, a threshold value Thresh1 and a threshold value Thresh2 are set in advance as threshold values for determining the presence or absence of motion in comparison with the image change amount MD. The threshold value Thresh1 is a threshold value for determining whether or not there is a motion, and the CPU 206 determines that there is no motion if the image change amount MD is less than the threshold value Thresh1.

  The threshold value Thresh2 is a slight movement that does not require switching to the video mode even if there is a movement, for example, when a shadow moves or a pen is placed in the still image mode. It is a threshold value for determining whether or not.

  If the image change amount MD is less than the threshold value Thresh2, the CPU 206 determines that the movement is slight enough not to switch to the moving image mode. The threshold value Thresh2 is set higher than the threshold value Thresh1 (Thresh1 <Thresh2). The memory 201 stores the threshold value Thresh1 and the threshold value Thresh2 in advance.

  Further, when switching from the moving image mode to the still image mode, the CPU 206 determines that there is no movement in the image, and switches the shooting mode to the still image mode after a predetermined time has elapsed. For this reason, the CPU 206 determines that there is no movement in the image and then measures the still time Ptime, and the memory 201 stores a predetermined time HoldTime set in advance for comparison with the still time Ptime.

  In addition, when the CPU 206 stores the high resolution image in the image storage area (high) 201a of the memory 201 after switching to the still image mode, the CPU 206 switches the resolution of the document camera 1 to the low resolution in order to detect motion in real time. Thus, the image change amount MD is calculated based on the low resolution image.

  In order to calculate the image change amount MD based on the low resolution image, the CPU 206 captures the document 4 at a low resolution, and uses the low resolution image data acquired by the image sensor 102 as the image storage area (low) 201b of the memory 201. To remember.

  The CPU 206 reads out the low resolution image stored in the image storage area (low) 201b when the document 4 is newly photographed at low resolution, and the low resolution image of the read data and the new low resolution obtained by photographing. The difference from the image is acquired as the image change amount MD.

  Note that when calculating the image change amount MD, the CPU 206 obtains an average luminance value of two low-resolution images in order to reduce the influence of the change in brightness. Make the average brightness of the two equal. The memory 201 stores the specified range of the average luminance value in advance.

  If the CPU 206 determines that there is a motion based on the image change amount MD, the CPU 206 waits until the motion of the image stops. When the motion stops, the CPU 206 determines the shooting mode after a predetermined time has elapsed.

  The CPU 206 includes a motion counter in order to determine the elapse of a predetermined time. The CPU 206 increments the count value after the movement stops, and compares the count value with a preset specified value to determine whether or not a predetermined time has elapsed. The memory 201 stores the count value and a preset specified value.

  The projector 2 irradiates the screen 3 with projection light and forms an image of the document 4. The document camera 1 and the projector 2 are connected via a cable 15 such as RGB. The document camera 1 outputs the image data of the document 4 photographed by the camera unit 11 to the projector 2 via the cable 15.

Next, the operation of the captured image projection apparatus according to this embodiment will be described.
When the user turns on the power of the document camera 1, the CPU 206 of the document camera 1 reads the program code from the program code storage device 205. When the user presses the shooting button, the operation unit 204 transmits this operation information to the CPU 206. The CPU 206 receives this operation information, and the CPU 206, the image processing device 203, etc. execute basic photographing processing.

The contents of this basic photographing process will be described with reference to the flowcharts shown in FIGS.
First, the CPU 206 initializes camera setting parameters such as focus, exposure, and white balance of the camera unit 11 of the document camera 1 (step S11).

  The CPU 206 initializes the shooting mode to the moving image mode (step S12). The CPU 206 sets the moving image mode (Motion) in the designated area on the memory 201 in order to initialize the shooting mode to the moving image mode. Further, the CPU 206 sets the image data read from the image sensor 102 of the camera unit 11 to be image data by VGA.

  As a result, the scene captured by the camera unit 11 is condensed on the image sensor 102 via the optical lens device 101, and the image sensor 102 creates a low-resolution digital image for moving image shooting from the collected image. To do. Then, the image sensor 102 sends out the created digital image to the memory 201 periodically, for example, at 30 sheets / second.

The CPU 206 resets the stationary time Ptime (step S13).
The CPU 206 controls the image sensor 102 and the memory 201 so that low-resolution image data is transmitted from the image sensor 102 to the memory 201 (step S14).
The CPU 206 stores the read low resolution image in the image storage area (low) 201b of the memory 201 (step S15).

  Here, only the image data of the image sensor 102 is transmitted to the memory 201, and the display device 202 does not display an image. The reason why the display device 202 does not display an image is that image data to be displayed on the display device 202 is stored in areas indicated by different addresses on the memory 201.

  The CPU 206 obtains the image change amount MD with respect to the previously photographed image according to Equation 1 (step S16).

The CPU 206 determines whether the shooting mode is the moving image mode or the still image mode (step S17).
In the initial state, the movie mode is set as the shooting mode. Therefore, the CPU 206 determines that the moving image mode is set in the initial state, and copies the moving image data stored in the memory 201 to the projected image storage area 201c of the memory 201 in order to project the captured moving image (step S18). . As a result, the display device 202 reads the captured image data from the memory 201 and outputs RGB signals to the projector 2. The projector 2 projects an image based on this signal.

  The CPU 206 compares the aforementioned threshold value Thresh1 set in advance with the image change amount MD obtained in step S16, and determines whether or not there is a motion based on the comparison result (step S19).

  At this time, if the user still continues the operation such as placing paper, the image change amount MD is equal to or greater than the threshold value Thresh1. In this case, the CPU 206 determines that there is a motion in the image (Yes in step S19), resets the still time Ptime, reads low-resolution image data, obtains an image change amount MD, and stores the image change amount in the image memory 201. Writing to the projected image storage area 201c is performed (steps S13 to S18). As a result, while the user performs an operation, the captured image projection device continues to maintain the moving image mode state, and a low resolution moving image is projected onto the screen 3.

  After that, when the user finishes setting the paper and the image stops moving, the image change amount MD becomes less than the threshold value. In this case, the CPU 206 determines that there is no motion in the image (No in step S19), and adds 1 to the still time Ptime (step S20).

  Then, the CPU 206 determines whether or not the stationary time Ptime has reached a predetermined time HoldTime (step S21).

  If it is determined that the still time Ptime has not reached the predetermined time HoldTime (No in step S21), the CPU 206 reads low-resolution image data again and determines the image change amount MD until it determines that there is no motion in the image. If there is no movement, 1 is added to the stationary time Ptime (steps S14 to S20). In this case, since the stationary time Ptime is not reset, the stationary time Ptime is counted up every time the moving image is read by the CPU 206.

  If it is determined that the still time Ptime has reached the predetermined time HoldTime (Yes in step S21), the CPU 206 determines whether or not only the pedestal 13 is included in the captured image, that is, the captured image includes the document image. It is determined whether or not (step S22).

  When it is determined that the photographed image does not include the document image (only the pedestal 13) (Yes in step S22), the CPU 206 does not perform processing such as image correction (processing in steps S23 to S26) by the image processing device 203. To control.

  On the other hand, if the CPU 206 determines that the photographed image includes a document image (not just the pedestal 13) (No in step S22), the CPU 206 sets the photographing mode to the still image mode (step S23).

  The CPU 206 controls the image sensor 102 so as to capture a high-resolution still image (step S24).

The image processing device 203 performs image correction processing on the captured image (step S25).
In other words, the image processing apparatus 203 extracts projection parameters for performing oblique correction on the read high-resolution still image, and cuts out an imaging target and performs projection conversion to a front image according to the projection parameters. I do.

  The image processing apparatus 203 extracts image effect correction parameters in order to convert the created corrected image into a clear and easily identifiable image such as contrast correction, and uses the image effect correction parameters to perform image effect correction. Process.

  The CPU 206 writes the corrected image data in the image storage area (high) 201a of the memory 201 in the same manner as in the case of the moving image, in order to project the image data subjected to the image effect processing. Then, the CPU 206 outputs image data to the projector 2 as RGB signals from the display device 202 (step S26).

  The CPU 206 clears the image data stored in the image storage area (low) 201b of the memory 201 (step S27).

The CPU 206 clears the count value of the motion counter (step S28).
The CPU 206 takes out the already read low resolution image from the image storage area (low) 201b of the memory 201 (step S29).

The CPU 206 controls the image sensor 102 to read a low resolution image (step S30).
The CPU 206 stores the read low resolution image in the image storage area (low) 201b of the memory 201 (step S31).

  The CPU 206 obtains the average brightness of the read low-resolution image and determines whether or not this average brightness is within a specified range (step S32).

  If it is determined that the average brightness is not within the specified range (No in step S32), the CPU 206 cannot compare the low resolution image extracted from the image storage area (low) 201b of the memory 201 with the read low resolution image. Steps S29 to S31 are executed again.

  If it is determined that the average luminance is within the specified range (Yes in step S32), the CPU 206 adjusts the luminance values of the two low-resolution images so that the two average luminances match (step S33).

The CPU 206 detects the image change amount MD according to Equation 1 (step S34).
The CPU 206 compares the detected image change amount MD with the threshold value Thresh1, and determines whether or not the image change amount MD exceeds the threshold value Thresh1 (step S35).

  When it is determined that the image change amount MD does not exceed the threshold value Thresh1 (MD ≦ Thresh1; No in step S35), the CPU 206 executes steps S28 to S34 again.

  When it is determined that the image change amount MD has exceeded the threshold value Thresh1 (MD> Thresh1; Yes in step S35), the CPU 206 increments the count value of the motion counter by one (step S36).

The CPU 206 determines whether or not the count value of the motion counter is equal to or greater than a specified value (step S37).
When it is determined that the count value of the motion counter is less than the specified value (No in step S37), the CPU 206 executes steps S29 to S36 again.

  When it is determined that the count value of the motion counter is equal to or greater than the predetermined value (Yes in step S37), the CPU 206 resets the still time Ptime again, reads a low-resolution image, and obtains the image change amount MD (steps S13 to S16). ).

  Here, when it is determined that the shooting mode is the still image mode (No in step S17), the CPU 206 compares the obtained image change amount MD with the threshold Thresh2 (Thresh1 <Thresh2) to determine whether or not there is a motion in the image. Is determined (step S38).

  If the image change amount MD exceeds the threshold value Thresh2, the CPU 206 determines that the image has a motion (Yes in step S38), and sets the shooting mode to the moving image mode (step S39). Then, the CPU 206 resets the stationary time Ptime (step S13).

  If the image change amount MD is equal to or smaller than the threshold value Thresh2, the CPU 206 determines that there is no movement in the image (No in step S38). In this case, the CPU 206 continues to compare the image change amount MD with the threshold value Thresh1, and determines whether or not there is a motion in the image (step S40).

  Even if the image change amount MD is equal to or less than the threshold value Thresh2, if the image change amount MD exceeds the threshold value Thresh1, the CPU 206 determines that the image has a motion (Yes in step S40). In this case, since the image change amount MD is between the threshold value Thresh1 and the threshold value Thresh2, the CPU 206 does not switch the shooting mode to the moving image mode (steps S22 to S26).

  If the image change amount MD is less than the threshold value Thresh2 and less than the threshold value Thresh1, the CPU 206 determines that the still state continues (No in step S40). In this case, the CPU 206 returns to step 13.

  In this way, the CPU 206 performs projection control while switching between the moving image mode and the still image mode. Thereby, while the user is performing the operation, the frame frequency priority image is projected, and when the image is stationary, the document 4 to be imaged is cut out and the image effect processing is performed to project the high resolution image. Done.

Next, the photographing process executed by the CPU 206 will be specifically described.
The CPU 206 initializes to the moving image mode and reads a low resolution image (processing of steps S11 to S14).

  In this case, as shown in FIG. 6, the CPU 206 reads the low-resolution image (1) and stores the read low-resolution image in the image storage area (low) 201b of the memory 201 (steps S14 and S15). The CPU 206 copies the low resolution image (1) to the projected image storage area 201c of the memory 201 (step S18).

  Next, the CPU 206 retrieves the low resolution image (1) from the image storage area (low) 201b of the memory 201, reads the low resolution image (2), and reads the read low resolution image into the image storage area (low) of the memory 201. 201b (processing in steps S14 and S15).

  The CPU 206 compares the low resolution images (1) and (2) to determine whether or not there is movement in the image (step S19), and when the image is moving due to replacement of the document 4 or the like, This process (steps S13 to S18) is periodically performed.

  When the movement of the image is stopped and the still time Ptime reaches the predetermined time HoldTime as in the case where the document 4 is placed on the pedestal 13, the CPU 206 sets the shooting mode to the still image mode, A still image is taken with a high resolution (steps S13 to S24).

  Then, the image processing device 203 performs image correction processing, and the CPU 206 stores the image data subjected to the image correction processing in the projection image storage area 201c of the memory 201 (steps S25 and S26).

  When the image data is stored in the projected image storage area 201c of the memory 201, the CPU 206 clears the image storage area (low) 201b of the memory 201 and clears the count value of the motion counter (steps S27 and S28). .

  The CPU 206 reads the low resolution image (3) (processing of steps S29 and S30). The CPU 206 stores the read low resolution image (3) in the image storage area (low) 201b (processing in step S31).

  If there is no motion in the image, the image change amount MD between the low resolution image (1) and the low resolution image (2) is equal to or less than the threshold value Thresh1, and the CPU 206 performs processing (steps S28 to S34) until the image moves. repeat.

  When the image moves, the moving image stops, and the still time Ptime reaches the predetermined time HoldTime, the CPU 206 sets the shooting mode to the still image mode and takes a still image with high resolution (steps S13 to S24). Processing).

  Then, when the image data is stored in the projected image storage area 201c of the memory 201, the CPU 206 repeats the same processing, and sequentially, low resolution images (3) and (4), low resolution images (4) and ( 5) is compared to determine whether there is any motion in the image.

  As described above, according to the first embodiment, after setting the resolution of the camera to a high resolution, the resolution is switched to a low resolution to determine the presence or absence of image motion. Therefore, in low-resolution shooting, since a low-resolution image can be captured at about 10 frames / second, the presence / absence of image movement can be determined in real time.

(Embodiment 2)
As shown in FIG. 7, the captured image projection apparatus according to the second embodiment captures a high-resolution image, and then reads the low-resolution image (2) immediately before setting the high-resolution image when the low-resolution image (3) is read. ) And the newly read low-resolution image (3).

Next, the operation of the captured image projection apparatus according to the second embodiment will be described.
The document camera 1 according to the second embodiment operates in accordance with the flowcharts shown in FIGS. As in the first embodiment, the CPU 206 determines whether or not there is a motion in the image based on the low resolution image (steps S11 to S19). As in the first embodiment, the CPU 206 stores the read low-resolution image in the image storage area (low) 201b of the memory 201 when the image is moving (steps S14 and S15).

  The CPU 206 of the second embodiment determines that there is motion in the image, and when the still time Ptime has passed the predetermined time HoldTime, sets the shooting mode to the still image mode and captures a still image with high resolution (steps S19 to S24). Processing).

  Then, the image processing device 203 performs image correction processing, and the CPU 206 stores the image data subjected to the image correction processing in the projected image storage area 201c of the memory 201 (steps S24 and S25).

After high-resolution imaging, the CPU 206 according to the second embodiment determines whether or not there is a motion in the image according to the flowchart shown in FIG.
That is, the CPU 206 stores the image data in the projected image storage area 201c of the memory 201, and then clears the already read low resolution image without clearing the image data in the image storage area (low) 201b of the memory 201. (Low) 201b is taken out, a low resolution image is read, and the read low resolution image is stored in the image storage area (low) 201b (Steps S29 to S31).

  If the two low-resolution images are compared and the image change amount MD is equal to or less than the threshold Thresh1 (No in step S35), the CPU 206 determines that there is no motion and executes steps S28 to S34 again. .

  On the other hand, when the image change amount MD exceeds the threshold value Thresh1 (Yes in step S35), the CPU 206 determines that the image has motion, and resets the still time Ptime when the count value of the motion counter becomes equal to or greater than a specified value ( Step S13).

  As described above, according to the second embodiment, after capturing a still image with high resolution, a low-resolution image is read without clearing the image data in the image storage area (low) 201b of the memory 201. Judgment of movement was performed.

  Therefore, even when an image shot while switching to a high resolution is taken, for example, when a hand is photographed when placing a document, the display of the image can be stopped immediately.

(Embodiment 3)
As shown in FIG. 9, the captured image projection apparatus according to the third embodiment includes the last low-resolution image (2) before reading the high-resolution image and the low-resolution images (3), (4), (5) is sequentially compared to determine whether or not there is a motion in the image.

Next, the operation of the captured image projection apparatus according to the third embodiment will be described.
The document camera 1 according to the third embodiment operates according to the flowcharts shown in FIGS. As in the first embodiment, the CPU 206 determines whether or not there is a motion in the image based on the low resolution image (steps S11 to S19). As in the first embodiment, the CPU 206 stores the read low resolution image in the image storage area (low) 201b of the memory 201 when the image is moving (steps S14 and S15).

  The CPU 206 determines that the image has motion, and when the still time Ptime reaches the predetermined time HoldTime, sets the shooting mode to the still image mode and takes a still image with high resolution (processing of steps S19 to S24). .

  Then, the image processing device 203 performs image correction processing, and the CPU 206 stores the image data subjected to the image correction processing in the projected image storage area 201c of the memory 201 (steps S24 and S25).

After high-resolution imaging, the CPU 206 according to the third embodiment determines whether there is a motion in the image according to the flowchart illustrated in FIG.
That is, the CPU 206 takes out the last low-resolution image before performing high-resolution imaging from the image storage area (low) 201b of the memory 201 (step S51).

  The CPU 206 clears the count value of the motion counter and reads a low resolution image (steps S28 and S30). The CPU 206 determines whether or not the average luminance is within a specified range without storing the read low resolution image (step S32).

  If it is determined that the average luminance is within the specified range (Yes in step S32), the CPU 206 adjusts the luminance values of the two low-resolution images so that the two average luminances match, and the image change amount according to Equation 1 MD is detected (steps S33 and S34).

  When the two low-resolution images are compared and the image change amount MD is equal to or smaller than the threshold value Thresh1 (No in step S35), the CPU 206 determines that there is no movement in the image and repeats steps S51, S28, and S30- 34 is executed.

  On the other hand, when the image change amount MD exceeds the threshold value Thresh1 (Yes in step S35), the CPU 206 determines that the image has motion, and resets the still time Ptime when the count value of the motion counter becomes equal to or greater than a specified value ( Step S13).

  As described above, according to the third embodiment, the last low-resolution image before reading the high-resolution image and the low-resolution image sequentially read after reading the high-resolution image are compared, and the image is moved. Judgment whether or not there is.

  Accordingly, since the determination of the presence or absence of image movement does not depend on the comparison of two images before and after low-resolution shooting, even if the brightness changes due to flicker caused by a fluorescent lamp, the brightness change cycle and the image comparison It does not coincide with the timing, and an erroneous determination of the motion of the image can be prevented. And when an image stops still, it can switch to a still image mode correctly.

In carrying out the present invention, various forms are conceivable and the present invention is not limited to the above embodiment.
For example, in the first embodiment, every time the document camera 1 captures an image, two low resolution images are compared. However, if it is possible to determine the presence or absence of image movement without hindrance, the determination can be made every time shooting is performed twice or three times.

  In the third embodiment, the low resolution image immediately before switching to the high resolution shooting is used as a comparison target of the plurality of low resolution images after switching to the high resolution shooting. However, the image need not be a low-resolution image immediately before switching to high-resolution shooting as long as it can determine whether or not the document 4 is moving.

  In the above embodiment, the photographing apparatus has been described as a photographed image projection apparatus. However, it is not necessary to provide a projector. For example, the above-described embodiment can be applied even to a configuration in which the document 4 is photographed with a digital camera.

In the above-described embodiment, the program is described as being stored in advance in a memory or the like. However, a program for causing a computer to operate as the whole or a part of the apparatus or to execute the above-described processing is a flexible disk, a CD-ROM (Compact Disk Read-Only Memory), a DVD (Digital Versatile Disk), The information may be stored in a computer-readable recording medium such as an MO (Magneto Optical disk) and distributed, installed in another computer, operated as the above-described means, or the above-described 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 explanatory drawing which shows the whole structure of the picked-up image projection apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the document camera shown in FIG. FIG. 3 is a block diagram showing an image storage area of the memory shown in FIG. 2. It is a flowchart which shows the content of the imaging | photography process which the document camera shown in FIG. 1 performs. FIG. 2 is a flowchart showing the contents of photographing processing executed by the document camera shown in FIG. 1, and particularly shows the contents of determination performed by the document camera after high-resolution photographing. It is explanatory drawing for demonstrating the specific operation | movement of the document camera shown in FIG. It is explanatory drawing for demonstrating the specific operation | movement of the picked-up image projection apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows the content of the determination performed after the high resolution imaging | photography in the imaging | photography process by the picked-up image projection apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing for demonstrating the specific operation | movement of the picked-up image projection apparatus which concerns on Embodiment 3 of this invention. It is a flowchart which shows the content of the determination performed after the high resolution imaging | photography in the imaging | photography process by the picked-up image projection apparatus which concerns on Embodiment 3 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Document camera, 2 ... Projector, 3 ... Screen, 4 ... Original, 11 ... Camera part, 201 ... Memory, 202 ... Display apparatus, 203 ... Image Processing device, 204... Operation unit, 206... CPU

Claims (8)

A photographing device for photographing a document,
A photographing unit for photographing the original document at a low resolution or a high resolution;
When the document is photographed at a high resolution, the photographing unit is controlled to photograph the document by switching the resolution to a low resolution, and based on the low-resolution image of the document obtained by photographing by the photographing unit, the image A control unit for determining the presence or absence of movement,
An imaging apparatus characterized by that. A storage unit for storing a photographed image obtained by photographing of the photographing unit;
The control unit stores, in the storage unit, data of a low resolution image obtained by the imaging unit capturing the original at a low resolution, and newly captures the original at a low resolution from the low resolution image stored in the storage unit. The difference between the low-resolution image of the read data and the new low-resolution image obtained by shooting by the shooting unit is acquired as an image change amount, and the acquired image change amount is a preset threshold value. It is determined that the document has moved when
The imaging apparatus according to claim 1, wherein: A storage unit for storing a photographed image obtained by photographing of the photographing unit;
The control unit stores in the storage unit data of a low-resolution image obtained by photographing by the photographing unit before the photographing unit photographs the original at high resolution, and after photographing the original at high resolution. The low-resolution image data stored in the storage unit is read out from the storage unit, and the low-resolution image data newly obtained by the imaging unit is stored in the storage unit. The difference between the resolution image and the new low-resolution image obtained by photographing by the photographing unit is acquired as an image change amount, and it is determined that the document has moved when the acquired image change amount exceeds a preset threshold value. To
The imaging apparatus according to claim 1, wherein: A storage unit for storing a photographed image obtained by photographing of the photographing unit;
The control unit stores in the storage unit data of a low-resolution image obtained by photographing by the photographing unit before the photographing unit photographs the original at high resolution, and after photographing the original at high resolution. When the photographing unit photographs the original document at a low resolution, the low resolution image data before the high resolution photographing stored in the storage unit is read from the storage unit, and the low resolution image of the read data and the photographing are read out. A difference from a new low-resolution image obtained by image capturing is acquired as an image change amount, and it is determined that the document has moved when the acquired image change amount exceeds a preset threshold value;
The imaging apparatus according to claim 1, wherein: The control unit acquires an average brightness of a new low-resolution image obtained by shooting of the shooting unit, determines whether or not the acquired average brightness is within a preset specified range, and the average brightness is the If determined to be within the specified range, the average luminance of the low-resolution image of the data read from the storage unit and the average luminance of the new low-resolution image obtained by shooting of the shooting unit match each other. Adjusting each pixel value of the low-resolution image to obtain the image change amount;
The photographing apparatus according to claim 2, wherein the photographing apparatus is characterized in that: When the average brightness of the new low-resolution image obtained by the photographing by the photographing unit exceeds a preset specified value, the control unit then obtains a new low-resolution image obtained by the photographing by the photographing unit. Obtaining a resolution image and determining whether the average luminance of the obtained low-resolution image is within the specified range;
The imaging device according to claim 5, wherein: A step of shooting a document in high resolution;
Switching the resolution to a low resolution and shooting the document at a low resolution;
Determining the presence or absence of movement of the image based on a low-resolution image of the document obtained by photographing the document at a low resolution.
An imaging processing method characterized by the above. On the computer,
Procedure for shooting a document at high resolution,
A procedure for switching the resolution to a low resolution and shooting the document at a low resolution;
A procedure for determining the presence or absence of movement of the image based on a low-resolution image of the document obtained by photographing the document at a low resolution;
A program for running