JP4487771B2 - Imaging apparatus, imaging method, and program - Google Patents

Description

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

  2. Description of the Related Art In recent years, there is a photographing apparatus that photographs a document placed on a pedestal with a camera and projects a photographed image obtained by photographing on a screen using a projector (see, for example, Patent Document 1).

As such an image pickup apparatus, there is an apparatus that determines that the document has moved when the document is replaced, and performs main shooting for acquiring an image of the document only at this time.
JP 2002-354331 A (page 2-3, FIG. 1)

  However, in such a photographing apparatus, for example, when the desk on which the camera is installed shakes or a shadow enters the photographing range, the original is not moving but the original is moving. Misjudgment. If erroneous determination is made in this way, the photographing apparatus performs unnecessary photographing.

  SUMMARY An advantage of some aspects of the invention is that it provides a photographing apparatus, a photographing method, and a program capable of preventing unnecessary photographing.

In order to achieve this object, an imaging device according to the first aspect of the present invention provides:
In a photographing device for photographing a pedestal on which a document is placed ,
The pedestal is one in which an identification mark is pre-marked at a position where the document is placed,
An imaging unit that performs imaging toward a position on the pedestal where the document is placed;
When it is determined whether or not the identification mark is included in the captured image obtained by causing the imaging unit to perform provisional imaging, and when it is determined that the identification mark image is included in the captured image, A first determination unit that determines a change in a captured image based on a captured image obtained by repeatedly performing provisional capturing on the capturing unit, and determines whether or not the captured image has moved;
When said first determination unit that there is a motion in the photographed image is determined, the include indicia image indicia in the captured image when said first determination unit has to perform the temporary photographing the photographing unit A second determination unit that re-determines whether or not
When the second determination unit determines that the identification mark image of the identification mark is included in the photographed image, the determination of the first determination unit is an erroneous determination to acquire the image of the document. A photographing control unit that controls the photographing unit so as not to perform the main photographing.

  When the second determination unit determines that the identification image of the identification mark is not included in the captured image, the imaging control unit assumes that the determination of the second determination unit is correct and the actual imaging You may make it control the said imaging | photography part so that it may perform.

  The second determination unit scans the captured image, counts the pixel values of the image of the identification mark in the scanning direction, generates a projection histogram, and corresponds to the image of the identification mark from the generated projection histogram. When a pattern is detected, it may be determined that the image of the identification mark is included in the captured image.

  The first determination unit obtains a difference between each pixel value of the photographed image at the time of previous provisional photographing and a pixel value of the photographed image at the time of current provisional photographing for all pixels, and sums all the obtained differences. It may be acquired as an image change amount of a captured image, and the change in the captured image may be determined by comparing the acquired image change amount with a preset threshold value.

The imaging method according to the second aspect of the present invention is:
A photographing method for photographing a pedestal on which a document is placed and on which an identification mark is previously written ,
Temporary photographing is performed as temporary photographing for determination for determining whether or not the identification mark is included in the photographed image, and whether or not the identification mark image of the identification mark is included in the obtained photographed image. A determining step;
When it is determined that the identification mark image is included in the captured image, a step of repeatedly capturing the pedestal as a temporary image for determining a motion of the captured image;
Determining a change in the photographed image based on a photographed image obtained by repeatedly performing provisional photographing for motion determination, and determining whether the photographed image has moved as a first determination;
If it is determined that there is motion in the captured image , as the second determination, whether or not the identification mark image of the identification mark is included in the captured image when the temporary determination for motion determination is performed in the first determination. Re-determining
If it is determined in the second determination that the photographed image includes an identification mark image of the identification mark, the first determination is an erroneous determination, and actual photographing for obtaining the image of the document is performed. And a step for preventing it.

The program according to the third aspect of the present invention is:
On the computer,
A procedure for determining whether or not the identification mark is included in a photographed image obtained by provisional photographing on a pedestal on which an original is placed and on which an identification mark is written in advance,
When it is determined that the identification mark is included in the photographed image, a procedure for repeatedly photographing the pedestal as provisional photographing for image movement determination;
A procedure for determining a change in the captured image based on a captured image obtained by repeatedly performing provisional capturing for motion determination, and determining, as a first determination, whether the captured image has moved;
If it is determined that there is motion in the captured image , as the second determination, whether or not the identification mark image of the identification mark is included in the captured image when the temporary determination for motion determination is performed in the first determination. The procedure to re-determine
If it is determined in the second determination that the photographed image includes an identification mark image of the identification mark, the first determination is an erroneous determination, and actual photographing for obtaining the image of the document is performed. Steps to avoid,
Is to execute.

  According to the present invention, unnecessary actual photographing can be prevented.

Hereinafter, an imaging device according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows the configuration of the photographing apparatus according to this embodiment.
The photographing apparatus includes a document camera 1 and a projector 2. The document camera 1 and the projector 2 are connected via a video image cable 31.

  The document camera 1 is a camera system for shooting a shooting target, and includes a camera unit 11, a support column 12, and a pedestal 13. 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 support column 12, and as shown in FIG. 2, a cross mark 14 is engraved at a substantially central portion of the pedestal 13. The cross mark 14 is stamped to identify whether or not the document 4 is placed, and an area including the central portion of the pedestal 13 is a placement position on which the document 4 is placed.

  The camera unit 11 photographs the document 4 placed on the pedestal 13 and shoots toward the center of the pedestal 13. The document camera 1 cuts out a document image of a document 4 portion (paper) from a photographed image obtained by the camera unit 11 and performs a process for detecting oblique photographing distortion so that the document image is seen as if the document 4 was viewed from the front. The image is converted into a photographed image and projected onto the screen 3.

  For this reason, the document camera 1 includes an image data generation unit 21 and a data processing unit 22, as shown in FIG. The image data generation unit 21 captures the document 4 and captures document image data.

  The data processing unit 22 acquires image data to be photographed from the image data generation unit 21 and processes an image for output to the projector 2.

  The image data generation unit 21 is provided in the camera unit 11 and includes an optical lens device 101 and an image sensor 102.

  The optical lens device 101 is composed of a lens for condensing light for photographing the document 4, and includes a peripheral circuit for adjusting camera setting parameters such as focus, exposure, and white balance.

  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 data generation unit 21 can perform high-resolution image capturing and low-resolution image capturing. Low-resolution image shooting is, for example, shooting performed at an image resolution of about XGA (1024 × 768 dots), and although the resolution is low, moving images and image reading are performed at a speed of 30 fps (frames / second). It becomes possible.

  On the other hand, high-resolution image capturing is image capturing performed with the maximum number of pixels of the camera unit 11 although the reading speed is slow. For example, when the maximum number of pixels that can be captured by the camera unit 11 is 4 million pixels, in high-resolution image capturing, image capturing is performed with 4 million pixels.

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

  The memory 201 stores image data, various flag values, threshold values, and the like, and is also used to store work data of the CPU 206.

  The video output device 202 generates RGB signals based on image data stored in the memory 201 as projection processing. The video output device 202 outputs the generated RGB signal to the projector 2.

  The image processing device 203 is controlled by the CPU 206 to perform image processing on the image data temporarily stored in the memory 201. The image processing apparatus 203 performs document image clipping processing and projection correction processing as image processing.

  The document image cutting process is a process of cutting a document image from a photographed image. Projection correction processing is processing for correcting distortion of a document image by performing projective conversion on the cut document image. The image processing apparatus 203 stores the image data on which distortion correction has been performed in the memory 201.

  The operation unit 204 is for acquiring user operation information, and includes a power switch and a shutter (not shown) as switches and keys for controlling the functions of the photographing apparatus.

  The power switch is for turning the power of the document camera 1 on (ON) and off (OFF). The shutter is a switch that is pressed during shooting.

  The operation unit 204 outputs operation information when the user operates switches and keys to the CPU 206.

  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 according to a program stored in the program code storage device 205 and executes photographing processing.

  Specifically, the CPU 206 first initializes each unit in the photographing process. That is, the CPU 206 performs initialization of peripheral circuits of the optical lens device 101, camera settings such as the focus, zoom lens position, and aperture of the optical lens device 101, and initialization of the video output device 202 and the like.

  The CPU 206 initializes data used for initialization of the memory 201, communication, image processing, and the like.

  Further, the CPU 206 initializes each data relating to the conditions for performing camera shooting, such as camera focus, shutter speed (exposure time), exposure of the aperture, white balance, ISO sensitivity, etc., auto focus measurement, Perform photometry, etc., and search for conditions that optimize shooting, and perform initialization.

  When such initialization is performed, the CPU 206 controls each unit so as to perform main photographing for image processing of an image of the document 4 when the document 4 moves.

  When the CPU 206 determines whether or not the document 4 has moved, for example, the desk on which the document camera 1 is installed shakes or a shadow falls within the shooting range, so that the document 4 is erroneously moved. The following determination is performed so as not to determine.

  That is, the CPU 206 controls the image data generation unit 21 to perform temporary shooting, and determines whether or not the image of the cross mark 14 is included in the captured image obtained by the temporary shooting. The provisional shooting is for making this determination, and the CPU 206 controls the image data generation unit 21 so as to perform shooting at a low resolution that can make this determination.

  If the image of the cross mark 14 is included in the captured image, the CPU 206 determines that the document 4 is not placed on the pedestal 13. On the other hand, if the image of the cross mark 14 is not included in the captured image, the CPU 206 determines that the document 4 is placed on the pedestal 13.

  In order to make this determination, the CPU 206 causes the image processing device 203 to create a binary edge image and create an edge image qj as shown in FIG. Then, the CPU 206 detects a cross edge image 14j corresponding to the cross mark 14 stamped on the pedestal 13.

  The CPU 206 scans the center portion Area_1 shown in FIG. 4A in the vertical scanning direction, counts the number of pixels of the cross-edge image 14j, and creates a histogram Hv as shown in FIG. 4B.

  When the crossed edge image 14j is included in the captured image, two peak values appear at intervals corresponding to the width of the crossed edge image 14j.

  The CPU 206 sets a threshold value Hv_th as shown by a broken line in FIG. 4B for the number of pixels of the created histogram Hv. This threshold value Hv_th is a threshold value set in advance to detect the peak value of the number of pixels in the vertical scanning direction from the cross edge image 14j.

  Similarly, in the horizontal scanning direction, the CPU 206 scans the central portion Area_1 in the horizontal scanning direction, counts the number of pixels of the cross-edge image 14j, and creates a histogram Hh. Then, the CPU 206 sets a threshold value Hh_th for the number of pixels of the created histogram Hh.

  Note that the memory 201 stores the threshold value Hv_th and a threshold value Hh_th set in advance for the number of pixels of the histogram Hv in the horizontal scanning direction.

  If there are no two peak values that exceed the threshold values Hv_th and Hh_th in the vertical scanning direction and the horizontal scanning direction, respectively, the CPU 206 places the cross mark 14 on the captured image because the document 4 is placed on the pedestal 13. Is determined not to be included. On the other hand, when the two peak values exceed the threshold values Hv_th and Hh_th, the CPU 206 determines that the cross mark 14 is included in the captured image because the document 4 is not placed on the pedestal 13.

  When the CPU 206 determines that the image of the cross mark 14 is included in the photographed image, the CPU 206 controls the image data generation unit 21 to determine a change in the photographed image obtained by repeatedly performing provisional photographing. Then, the CPU 206 determines whether or not the document 4 has moved.

  In order to make this determination, the CPU 206 acquires, for all pixels, the difference between each pixel value of the captured image at the time of previous provisional photographing and the pixel value of the photographed image at the time of current provisional photographing. The CPU 206 acquires the sum of all the acquired differences as the image change amount MD of both captured images, and determines the change in the captured image by comparing the acquired image change amount MD with a preset threshold value MD_th. The threshold value MD_th is set in advance to make this determination, and the memory 201 stores the threshold value MD_th in advance.

  If the image change amount MD exceeds the threshold value MD_th, the CPU 206 determines that the document 4 has motion, and if it is equal to or less than the threshold value MD_th, determines that the document 4 has no motion.

  If the CPU 206 determines that the document 4 is moving, the CPU 206 re-determines whether or not the image of the cross mark 14 is present in the captured image when provisional shooting is performed. The CPU 206 generates the above-described projection histogram, and performs this determination by performing processing for detecting the pattern of the cross-edged image 14j using the generated projection histogram.

  This determination is made so as not to erroneously determine that the document 4 is moving when, for example, the desk on which the document camera 1 is installed shakes or a shadow enters the shooting range.

  That is, when a shadow appears in the shooting range in a state where the document 4 is not placed on the pedestal 13, the cross mark 14 on the pedestal 13 remains visible. If the captured image has a cross-edge image 14j, the projection histogram includes two peak values that exceed the thresholds Hv_th and Hh_th as a pattern corresponding to the cross-edge image 14j.

  The CPU 206 detects these two peak values, and when these two peak values are detected, it is determined that the document 4 is in motion because a shadow is included in the generated shooting range or the desk is shaken. If it is determined that the document 4 is in motion, it is determined as an erroneous determination. If the CPU 206 determines that there is an erroneous determination in this manner, the CPU 206 controls the image data generation unit 21 so as not to perform the main photographing for acquiring the document image.

  On the other hand, if the CPU 206 does not detect these two peak values, the cross mark 14 imprinted on the pedestal 13 is hidden by the document 4 placed on the pedestal 13, and the document 4 has movement. Is determined to be correct. If the CPU 206 determines that it is correct in this way, it controls the image data generation unit 21 to perform the main photographing.

  That is, the CPU 206 controls the image data generation unit 21 to switch the shooting resolution to a high resolution, thereby executing the shooting enabled process and acquiring a clear image.

  Then, the CPU 206 causes the image data generation unit 21 to perform actual shooting, and controls the image processing device 203 and the video output device 202 to execute image processing and projection processing.

  The projector 2 converts the image data supplied from the document camera 1 into projection light, and irradiates the projection light on the screen 3 to form an original image on the screen 3.

Next, the operation of the photographing apparatus according to the present 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 and executes camera basic processing.

The contents of this camera basic projection process will be described with reference to the flowchart shown in FIG.
The CPU 206 performs camera settings such as the focus, zoom lens position, and aperture of the optical lens device 101, initialization of the video output device 202 and the like, and initialization of data (step S11).

  The CPU 206 controls the image data generation unit 21 to perform temporary shooting for determination (step S12).

  The CPU 206 determines whether or not the image of the cross mark 14 is included in the captured image obtained by provisional imaging (step S13).

If it is determined that no image is included in the cross mark 14 in the captured image (No in step S13), CPU 206 determines that the document 4 to the base 13 rests again performs provisional imaging (step S12).

If it is determined that the image of the cross mark 14 is included in the captured image (Yes in step S13), the CPU 206 determines that the document 4 is not placed on the pedestal 13 and performs provisional shooting (step S14). ).

  The CPU 206 reads the data of the photographed image at the previous photographing already stored in the memory 201 (step S15).

  The CPU 206 obtains an image change amount MD between the read image data at the previous photographing and the image data at the current photographing newly captured by the image sensor 102 (step S16).

  The CPU 206 stores the image data at the time of the current shooting in the memory 201 for comparison with the next image to be shot (step S17).

  The CPU 206 reads the threshold value MD_th from the memory 201 and compares the obtained image change amount MD with the read threshold value MD_th to determine whether or not the document 4 has moved (step S18).

  When the image change amount MD is equal to or smaller than the threshold value MD_th, the CPU 206 determines that the document 4 has no movement (No in step S18). Then, the CPU 206 executes steps S14 to S17 again.

  When the image change amount MD exceeds the threshold value MD_th, the CPU 206 determines that there is a motion in the document 4 (Yes in step S18). In this case, the CPU 206 determines whether or not the image of the cross mark 14 is included in the photographed image obtained by the provisional photographing acquired in step S14 (step S19).

  That is, the CPU 206 scans the captured image obtained by the temporary capturing acquired in step S14, generates a projection histogram, and has two peaks that exceed the thresholds Hv_th and Hh_th as a pattern corresponding to the cross-edge image 14j. Perform value detection processing

  When it is determined that the image of the cross mark 14 is included in the captured image by detecting the two peak values (Yes in step S19), the CPU 206 determines that the document 4 has moved is an erroneous determination. judge. If CPU206 determines in this way, it will perform step S14-S18 again.

  If it is determined that the image of the cross mark 14 is not included in the captured image because the two peak values are not detected (No in step S19), the CPU 206 determines that the document 4 has moved. Is determined. In this case, the CPU 206 executes a shootable process (step S20).

  The CPU 206 controls the image data generation unit 21 to perform main photographing for acquiring a document image (step S21).

The image processing apparatus 203 executes a document image clipping process (step S22).
The image processing apparatus 203 executes a projection correction process for the clipped document image (step S23).

  The image processing apparatus 203 stores the corrected document image data in the memory 201 (step S24). The video output device 202 reads the corrected image data from the memory 201 and supplies it to the projector 2. The projector 2 projects a document image on which distortion correction has been performed based on this data onto the screen 3.

  As described above, according to the present embodiment, the cross mark 14 is engraved on the pedestal 13 in advance, and the CPU 206 performs provisional shooting and determines whether or not the image of the cross mark 14 is included in the shot image. . If it is determined that the image of the cross mark 14 is included, the CPU 206 performs provisional shooting and determines whether or not the document 4 has moved.

  When it is determined that the document 4 has motion, the CPU 206 re-determines whether or not the image of the cross mark 14 is included in the captured image by this temporary shooting. When it is determined that the image of the cross mark 14 is not included, the CPU 206 determines that the document 4 is placed on the pedestal 13 and performs a photographing process.

  Therefore, for example, even if the document 4 does not move, even if the desk on which the camera unit 11 is installed shakes or a shadow falls within the shooting range, the imaging apparatus erroneously determines that the document 4 has moved. Can be prevented, and unnecessary actual photographing can be prevented.

In carrying out the present invention, various forms are conceivable and the present invention is not limited to the above embodiment.
For example, the photographing apparatus may include a computer. The computer may have the function of the document camera 1, and the computer may perform image processing or the like. In this way, a general-purpose digital camera can be used for the camera unit 11.

  In the above embodiment, the programs are described as being stored in advance in a memory or the like. 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 imaging device which concerns on embodiment of this invention. It is a figure which shows the base and cross mark which are shown in FIG. It is a block diagram which shows the structure of the document camera shown in FIG. It is a figure which shows the detection process of a cross edge image. It is a flowchart which shows the imaging | photography process which the imaging device shown in FIG. 1 performs.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Document camera, 2 ... Projector, 3 ... Screen, 4 ... Document, 11 ... Camera part, 13 ... Base, 201 ... Memory, 202 ... Video output Device 203... Image processing device 204.

Claims (6)

In a photographing device for photographing a pedestal on which a document is placed ,
The pedestal is one in which an identification mark is pre-marked at a position where the document is placed,
An imaging unit that performs imaging toward a position on the pedestal where the document is placed;
When it is determined whether or not the identification mark is included in the captured image obtained by causing the imaging unit to perform provisional imaging, and when it is determined that the identification mark image is included in the captured image, A first determination unit that determines a change in the captured image based on a captured image obtained by causing the capturing unit to repeatedly perform temporary capturing, and determines whether or not the captured image has moved;
When said first determination unit that there is a motion in the photographed image is determined, the include indicia image indicia in the captured image when said first determination unit has to perform the temporary photographing the photographing unit A second determination unit that re-determines whether or not
When the second determination unit determines that the identification mark image of the identification mark is included in the photographed image, the determination of the first determination unit is an erroneous determination to acquire the image of the document. An imaging control unit that controls the imaging unit so as not to perform main imaging,
An imaging apparatus characterized by that. When the second determination unit determines that the identification image of the identification mark is not included in the captured image, the imaging control unit assumes that the determination of the second determination unit is correct and the actual imaging Controlling the photographing unit to perform
The imaging apparatus according to claim 1, wherein: The second determination unit scans the captured image, counts the pixel values of the image of the identification mark in the scanning direction, generates a projection histogram, and corresponds to the image of the identification mark from the generated projection histogram. When a pattern is detected, it is determined that the image of the identification mark is included in the captured image.
The photographing apparatus according to claim 1 or 2 , characterized in that The first determination unit obtains a difference between each pixel value of the photographed image at the time of previous provisional photographing and a pixel value of the photographed image at the time of current provisional photographing for all pixels, and sums all the obtained differences. It is acquired as an image change amount of the captured image, and the change of the captured image is determined by comparing the acquired image change amount with a preset threshold value.
The photographing apparatus according to any one of claims 1 to 3 , wherein A photographing method for photographing a pedestal on which a document is placed and on which an identification mark is previously written ,
Temporary photographing is performed as temporary photographing for determination for determining whether or not the identification mark is included in the photographed image, and whether or not the identification mark image of the identification mark is included in the obtained photographed image. A determining step;
When it is determined that the identification mark image is included in the captured image, a step of repeatedly capturing the pedestal as a temporary image for determining a motion of the captured image;
Determining a change in the photographed image based on a photographed image obtained by repeatedly performing provisional photographing for motion determination, and determining whether the photographed image has moved as a first determination;
If it is determined that there is motion in the captured image , as the second determination, whether or not the identification mark image of the identification mark is included in the captured image when the temporary determination for motion determination is performed in the first determination. Re-determining
If it is determined in the second determination that the photographed image includes an identification mark image of the identification mark, the first determination is an erroneous determination, and actual photographing for acquiring the document image is performed. And a step to prevent,
An imaging method characterized by the above. On the computer,
A procedure for determining whether or not the identification mark is included in a photographed image obtained by provisional photographing on a pedestal on which an original is placed and on which an identification mark is written in advance,
When it is determined that the identification mark is included in the photographed image, a procedure for repeatedly photographing the pedestal as provisional photographing for image movement determination;
A procedure for determining a change in the captured image based on a captured image obtained by repeatedly performing provisional capturing for motion determination, and determining, as a first determination, whether the captured image has moved;
If it is determined that there is motion in the captured image , as the second determination, whether or not the identification mark image of the identification mark is included in the captured image when the temporary determination for motion determination is performed in the first determination. The procedure to re-determine
If it is determined in the second determination that the photographed image includes an identification mark image of the identification mark, the first determination is an erroneous determination, and actual photographing for obtaining the image of the document is performed. Steps to avoid,
A program for running

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