JP4225226B2 - Imaging apparatus, imaging control method for imaging apparatus, and program - Google Patents

Description

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

  In OHP, which reads and projects paper documents and OHP paper, with the development of digital cameras, there is an imaging device (document camera) of a method called a document camera that uses a digital camera instead of a method that uses a conventional line scanner. It is being developed.

  In this photographing apparatus, a user photographs a document placed on a document table with a camera, performs image processing on the photographed document image, and enlarges and projects the document image on a screen using a projector. Yes (see, for example, Patent Document 1).

Such an imaging apparatus is changing for a conventional OHP because it can image a three-dimensional imaging object that could not be obtained with a conventional OHP and project this image.
JP 2002-354331 A (page 2-3, FIG. 1)

  However, in the conventional photographing apparatus, since the document table is stationary, the document table is photographed with the same resolution as the document while the document is exchanged.

  When attempting to shoot by switching the resolution, it is necessary to determine whether the object to be photographed is only a document table or includes a document. As the determination method, for example, paying attention to the amount of edge included in the image of the object to be photographed, the image of the edge part of the document table is masked and acquired in advance as shown in FIG. It is conceivable to determine the presence or absence of a document by comparing it with the amount of edges in the image on the document table.

  However, for example, as shown in FIG. 17B, when the document is a document such as an out-of-focus photograph or a picture drawn with gradation, the document exceeds the angle of view of the camera. The amount of edges is reduced and it is difficult to detect edges. Therefore, such a document may be erroneously determined that the document is not placed on the document table.

  The present invention has been made in view of such conventional problems, and provides a photographing apparatus, a photographing control method for the photographing apparatus, and a program capable of appropriately acquiring an image of a desired photographing object. With the goal.

In order to achieve the above object, a photographing apparatus according to the first aspect of the present invention provides:
In a photographing apparatus for photographing a document placed on a document table including the document table,
A photographing unit that photographs the original together with the document table at a low resolution or a high resolution;
When determining whether or not the document is placed on the document stand based on a photographed image obtained by photographing of the photographing unit, if it is determined that the document is placed on the document stand, A control unit for setting the resolution of the photographing unit to a high resolution,
The control unit includes a first determination region for determining an edge portion of the original and an edge portion of the document table outside the first determination region in a photographed image obtained by photographing of the photographing unit. A second discriminating region for discriminating an edge portion is set in advance, the number of edge portions existing in the first discriminating region covering the image of the second discriminating region is counted, and the counted first The number of edge portions in which the number of edge portions of one discrimination region is less than a preset first threshold and covers the image of the first discrimination region and is included in the second discrimination region , And when the counted number of edge portions of the second determination area is less than a preset second threshold, it is determined that the document is placed on the document table. And

  The control unit counts the number of edge portions existing in the first determination region so as to cover the image of the second determination region, and the counted number of edge portions of the first determination region is preset. When the number of edges is less than the first threshold and covers the image of the first discrimination area, the number of edge portions included in the second discrimination area is counted, and the edges of the second discrimination area thus counted are counted. When the number of copies is less than a preset second threshold, it is preferable to determine that the document is placed on the document table.

The document table is preliminarily marked with an identification mark at a position corresponding to the first discrimination area for discriminating an edge portion of the document.
The control unit determines an image based on the identification mark when the number of edge portions of the second region is equal to or greater than the second threshold value, and determines that the image based on the identification mark is not determined. It is preferable to determine that the document is placed on the document table.
Further, when the control unit determines that the document is not placed on the document table, it is preferable that the resolution of the photographing unit is set to a low resolution.

  The control unit acquires a pixel value in the first determination region or the second determination region, and detects an edge portion based on a difference between pixel values of adjacent pixels among the acquired pixel values. It is preferable to count the number of edge portions.

  The control unit preferably determines whether or not the image of the document is included in the captured image by determining the shape of the image by the identification mark in the captured image.

The document table is preliminarily written with a cross mark formed by line segments intersecting each other as an identification mark set with the shape,
The control unit scans pixels of the photographed image in two different directions with respect to the two line segments forming the cross mark in the photographed image, and an edge portion corresponding to the cross-sign image is detected. It is preferable to determine the shape of the cross mark image in the captured image by determining whether or not it is.

In order to achieve the above object, an imaging control device for an imaging device according to the second aspect of the present invention provides:
In a photographing apparatus for photographing a document placed on a document table including the document table,
A photographing unit that photographs the original together with the document table at a low resolution or a high resolution;
When determining whether or not the document is placed on the document stand based on a photographed image obtained by photographing of the photographing unit, if it is determined that the document is placed on the document stand, A control unit for setting the resolution of the photographing unit to a high resolution,
The control unit includes a first determination region for determining an edge portion of the original and an edge portion of the document table outside the first determination region in a photographed image obtained by photographing of the photographing unit. A second discriminating region for discriminating an edge portion is set in advance, the number of edge portions existing in the first discriminating region covering the image of the second discriminating region is counted, and the counted first When the number of edge portions of one discrimination area is less than a preset first threshold, the number of edge portions included in the second discrimination area covering the image of the first discrimination area is determined. And counting and determining that the document is not placed on the document table if the counted number of edge portions of the second determination area is equal to or greater than a second threshold value set in advance. To do.

In order to achieve the above object, an imaging control method for an imaging apparatus according to the third aspect of the present invention provides:
A photographing control method of a photographing device for photographing a document placed on a document table,
Obtaining a photographed image including the document table by photographing;
A second discriminating portion for discriminating an edge portion including a first discriminating region for discriminating an edge portion due to the original and an edge portion due to the document table outside the first discriminating region from the photographed image obtained by photographing. And determining the number of edge portions existing in the first determination area, covering the image of the second determination area,
When the counted number of edge portions of the first discrimination region is compared with a preset first threshold value, and the counted number of edge portions of the first discrimination region is less than the first threshold value Counting the number of edge portions included in the second discrimination area covering the image of the first discrimination area;
When the counted number of edge portions of the second discrimination region is compared with a preset second threshold value, and the counted number of edge portions of the second discrimination region is less than the second threshold value Determining that the document is placed on the document table;
And a step of setting the resolution of the photographing unit to a high resolution when it is determined that the document is placed on the document table.

In order to achieve the above object, a program according to the fourth aspect of the present invention provides:
On the computer,
Photographing the document placed on the document table together with the document table;
A second discriminating portion for discriminating a first discriminating region for discriminating an edge portion due to a document and an edge portion including an edge portion due to the document table outside the first discriminating region from the photographed image obtained by the photographing. A step of counting the number of edge portions existing in the first determination area, covering the image of the second determination area,
When the counted number of edge portions of the first discrimination region is compared with a preset first threshold value, and the counted number of edge portions of the first discrimination region is less than the first threshold value , A procedure for counting the number of edge portions included in the second discrimination region covering the image of the first discrimination region;
When the counted number of edge portions of the second discrimination region is compared with a preset second threshold value, and the counted number of edge portions of the second discrimination region is less than the second threshold value Is a procedure for determining that the document is placed on the document table;
A procedure for setting a resolution when shooting the document placed on the document table to a high resolution when it is determined that the document is placed on the document table;
Is to execute.

  ADVANTAGE OF THE INVENTION According to this invention, the image of a desired imaging target object can be acquired appropriately.

  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 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 document 4 is replaced by the user. Therefore, there are a case where the document 4 is placed on the pedestal 13 and a case where the document 4 is not placed. Further, 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.

  The pedestal 13 is for supporting the column 12, and in this embodiment, as shown in FIG. 2, a rectangular area K is drawn on the inner side of the pedestal 13, and the center portion is preliminarily indicated by “+”. A cross mark J having a set shape is drawn in advance. The cross mark J is formed by intersecting two line segments, and whether or not the object to be photographed is the document stand is determined by whether or not the cross mark J is detected in the photographed image in the document stand determination process described later. It is used to determine whether or not.

  Further, 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 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 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.
The display device 202 is for displaying an image sent out to the projector 2.

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

  The image processing apparatus 203 performs distortion correction (trapezoid correction) from the image of the document 4 taken in an oblique state or rotated state with respect to the photographing surface of the camera unit 11 as shown in FIG. Thus, an image of the document 4 taken from the front as shown in FIG. 4B is generated. 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 and keys 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.

  As shown in FIG. 5, the operation unit 204 includes an upper enlargement key 211, a lower enlargement key 212, a left enlargement key 213, a right enlargement key 214, a right rotation key 215, and a left rotation key as image adjustment keys. 216, an enlargement key 217, a reduction key 218, and a shooting / cancellation key 219.

  An upper enlargement key 211, a lower enlargement key 212, a left enlargement key 213, and a right enlargement key 214 are projective conversion keys operated when performing projective conversion.

  The right rotation key 215 and the left rotation key 216 are rotation correction keys for adjusting the rotation of the image, respectively. The right rotation key 215 is a key operated when the image is rotated to the right, and the left rotation key. Reference numeral 216 denotes a key operated when the image is rotated to the left.

  The enlargement key 217 and the reduction key 218 are keys operated when performing image conversion such as image enlargement and reduction, respectively.

  The shooting / cancel key 219 is a key operated when shooting the document 4.

  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.

  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.

  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.

  Further, the CPU 206 determines whether or not the document 4 is placed on the pedestal 13 based on a photographed image obtained by photographing by the camera unit 11, and if the document 4 is placed on the pedestal 13. If determined, the resolution is set high.

  Therefore, as shown in FIG. 6, the CPU 206 sets a document edge portion determination area and a mask area in the captured image. The document edge portion determination region is a region wider than the rectangular region K for determining the edge portion by the document 4, and the mask region determines an edge portion including the edge portion by the base 13 outside the document edge portion determination region. For determining the edge portion existing in the document edge portion determination region.

  Further, when the CPU 206 determines a scratch on the pedestal 13 and determines an edge portion existing in the document edge portion determination region, the CPU 206 sets a mask region including this scratch image. The scratch is like a scratch on the pedestal 13. If such a scratch is present on the pedestal 13, it is difficult to distinguish the original image from the scratched image. In addition, this damage | wound is not restricted only to a case where it is a mere damage | wound, For example, the thing of the seal | sticker stuck on the pattern of the base 13 and the base 13 is also included.

  The reason why the CPU 206 determines the scratch on the pedestal 13 is to prevent the CPU 206 from erroneously determining that the document 4 is placed even if the document 4 is not placed on the pedestal 13. If the CPU 206 makes such an erroneous determination, the image processing apparatus 203 performs useless image correction processing even if the document 4 is not placed on the pedestal 13.

  In order to determine the scratch on the pedestal 13, the CPU 206 compares, for example, an image of the pedestal 13 having no scratch as a preset image for determining scratches with a captured image of only the pedestal 13 acquired by the image sensor 102. To do. If there is a difference between the two images as a result of the comparison, the CPU 206 determines that the pedestal 13 is damaged. When the CPU 206 determines a scratch on the pedestal 13, the image processing apparatus 203 is caused to generate mask data for masking a scratch image due to this scratch.

  The image processing apparatus 203 is controlled by the CPU 206 to generate a mask that covers the mask area. At this time, the image processing apparatus 203 can cover all the wound images in the mask area even if the orientation of the camera unit 11 at the time of registration of the scratch and the recognition of the base 13 is different due to the deflection of the base 13 or the like. A mask is generated by setting a mask area including the area around the scratch. That is, as shown in FIG. 7, when there is a scratch of one dot in the image, the image processing apparatus 203 sets an n-dot region around the scratch as a mask region. The mask area does not need to be square, and the image processing apparatus 203 sets the mask area based on the position where the scratch is detected by the deflection or other characteristics of the base 13. The image processing apparatus 203 sets the mask area in this way, generates mask data, and stores the generated mask data in the memory 201.

  Then, the CPU 206 reads out the mask generated by the image processing apparatus 203 from the memory 201, covers the scratched image, and determines whether the photographed image includes a document image.

  In order to make this determination, the CPU 206 first detects an edge portion included in the captured image. This edge portion represents the contour of the pedestal 13, the contour of the document 4, and the like.

  In order to detect the edge portion, the CPU 206 compares the difference value between the pixel values of adjacent pixels with a predetermined value PS set in advance, whereby an edge in an image obtained by the camera unit 11 capturing an image. Part. This predetermined value PS is preset in order to detect this edge portion.

  As shown in FIG. 8, the adjacent pixels are point 1 and point 2, and the pixel values are P1 and P2. The CPU 206 compares the difference value between the pixel value (P1) of the pixel point1 and the pixel value (P2) of the pixel point2 with the predetermined value PS. When the difference value is larger than the predetermined value PS, the CPU 206 Is determined to exist.

  Next, the CPU 206 compares the number of edge portions with a preset threshold value ES to determine whether or not the document 4 is placed on the pedestal 13, that is, the document 4 is included in the shooting target. It is determined whether or not. If the document 4 is placed on the pedestal 13, the number of edge portions increases as compared to the case where the document 4 is not placed on the pedestal 13. The threshold value ES is a value set in advance to determine whether or not the document 4 is placed on the pedestal 13. If the CPU 206 determines that the number of edge portions is equal to or less than the threshold value ES, the CPU 206 determines that the image to be captured does not include a document image and is an image of only the base 13. The memory 201 stores the preset predetermined value PS and threshold value ES.

Further, for example, as shown in FIG. 9, when it is difficult to detect an edge such as a photograph that is not in focus or a picture drawn with gradation, the CPU 206 covers the document edge portion discrimination area and covers the mask area. Count the number of edges. This is because the document 4 sometimes exceeds the angle of view of the camera unit 11. In this case, the number of edge portions in the document edge portion determination area is reduced, and the CPU 206 counts the number of edge portions in the mask area. This is again to determine whether or not the document 4 is placed on the pedestal 13. In this way, the CPU 206 prevents erroneous determination that the document 4 is not placed on the pedestal 13.
When the CPU 206 determines that the edge portion of the mask area is less than the specified value, the CPU 206 determines an image by the cross mark J of the pedestal 13 in the captured image shown in FIG.
As shown in FIGS. 10 and 11, the CPU 206 scans the pixels of the captured image in the vertical direction and the horizontal direction with respect to the two line segments forming the cross mark, and the edge portion corresponding to the cross mark image. By determining whether or not is detected, the shape of the cross mark image in the captured image is determined.

  Only when it is determined that the document 4 is placed on the pedestal 13, the CPU 206 extracts the image of the document 4 from the photographed image and causes the image processing device 203 to perform image processing such as image correction.

  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 photographing apparatus according to the first embodiment will be described.
When the user turns on the power of the photographing apparatus, 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 flowchart shown in FIG.
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 the created digital image to the memory 201 periodically, for example, at 30 sheets per second.

Next, the CPU 206 detects a scratch on the document table, and sets a region (mask region) where edge detection is not performed in the document table determination process described later (step S13).
This process will be described with reference to the flowchart of FIG.

  The CPU 206 controls the camera unit 11 to take an image of the document table for registering scratches in the moving image mode (step S41). The photographed digital image of the document table is supplied to the memory 201 via the image sensor 102.

  The CPU 206 reads the image on the document table from the memory 201, and detects an edge portion from the image (step S42).

  The CPU 206 determines that the point where the edge portion is detected on the image is a scratch on the document table, and sets the surrounding area as a mask area (step S43).

Next, the CPU 206 resets the stationary time Ptime (step S14).
Next, the CPU 206 controls the image sensor 102 and the memory 201 so as to transfer low-resolution image data from the image sensor 102 to the memory 201 (step S15). Here, only the image data of the image sensor 102 is transferred 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.

  Next, the CPU 206 obtains the image change amount MD with respect to the previously captured image according to the 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 (step S17: Yes), and copies the moving image data in the memory 201 to a predetermined area of the memory 201 in order to project the captured moving image (step S17: Yes). 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 area is performed (steps S14 to S18). As a result, while the user performs an operation, the photographing apparatus 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 S15 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.

When it is determined that the stationary time Ptime has reached the predetermined time HoldTime (Yes in step S21), the CPU 206 determines whether only the pedestal 13 is shown based on the captured image (step S22).
CPU206 performs the base determination process for performing this determination based on the flowchart shown in FIG.
First, the CPU 206 detects an edge portion from an image obtained by removing the area (mask area) set in step S43 from the acquired image (step S51).
Note that a specific edge detection method is the same as that in step S42 described above, and a description thereof will be omitted here.

  The CPU 206 performs the edge portion detection process described above along each line, and adds the number of edge portions detected in all adjacent lines. Then, the number of edge portions in the image is compared with a predetermined threshold value ES (step S52).

  If it is determined that the number of edge portions is greater than the threshold value ES (Yes in step S52), the CPU 206 determines that the imaging target is not the pedestal 13. On the other hand, if it is determined that the number of edge portions is equal to or less than the threshold value ES (No in step S52), the CPU 206 detects the edge portion from the portion of the mask region in the captured image that covers the image of the document edge portion determination region. This is performed (step S53).

  The CPU 206 performs the edge portion detection process described above along each line in the mask area, and adds the number of edge portions detected in all adjacent lines. Then, the number of edge portions in the mask area in the image is compared with a predetermined threshold value ES2 (step S54). If it is determined that the number of edge portions is equal to or less than the threshold value ES2 (No in step S54), the CPU 206 determines that the imaging target is not the pedestal 13.

On the other hand, if it is determined that the number of edge portions in the mask area is larger than the threshold value ES2 (Yes in step S54), the CPU 206 detects the cross mark J near the center of the base 13 (step S55).
The CPU 206 performs a cross recognition process for the cross mark J according to the flowchart shown in FIG.
First, as shown in FIG. 10, the CPU 206 detects a falling edge in the vertical direction near the center of the pedestal 13 (step S61). Then, the CPU 206 determines whether or not there are two or three falling edges with substantially the same ordinate (step S62). If it is determined that there is no falling edge (No in step S62), the CPU 206 determines that the photographic subject does not have the cross mark J, and ends this process.

  On the other hand, if it is determined that there are two or three falling edges with substantially the same ordinate (Yes in step S62), the CPU 206 detects a rising edge in the vertical direction near the center of the base 13 (step S63). ). Then, the CPU 206 determines whether or not there are two or three rising edges at substantially the same ordinate (step S64). If it is determined that there is no rising edge (No in step S64), the CPU 206 determines that the object to be imaged does not have the cross mark J, and ends this process.

  On the other hand, if it is determined that there are two or three rising edges at substantially the same ordinate (Yes in step S64), the CPU 206 causes the horizontal falling edge near the center of the base 13 as shown in FIG. Is detected (step S65). Then, the CPU 206 determines whether or not there are two or three falling edges with substantially the same abscissa (step S66). If it is determined that there is no falling edge (No in step S66), the CPU 206 determines that the object to be imaged does not have the cross mark J, and ends this process.

  On the other hand, if it is determined that there are two or three falling edges with substantially the same abscissa (Yes in step S66), the CPU 206 detects a rising edge in the horizontal direction near the center of the base 13 (step S67). ). Then, the CPU 206 determines whether or not there are two or three rising edges on substantially the same abscissa (step S68). If it is determined that there is no rising edge (No in step S68), the CPU 206 determines that the object to be imaged does not have the cross mark J, and ends this process.

  On the other hand, if it is determined that there are two or three rising edges at substantially the same abscissa (Yes in step S68), the CPU 206 determines whether the vertical and horizontal edges detected in steps S61 to 68 intersect. (Step S69). If it is determined that they do not intersect (No in step S69), the CPU 206 determines that the object to be imaged has no cross mark J, and ends this process.

  On the other hand, if it is determined that the vertical and horizontal edges intersect (Yes in step S69), the CPU 206 determines that the object to be photographed has the cross mark J and ends this processing.

  Through the series of processes shown in steps S61 to S69, the CPU 206 determines whether or not the cross mark J is present on the photographing target (step S56 in the flow of FIG. 14). If it is determined that the cross mark J does not exist in the shooting target (No in step S56), the CPU 206 determines that the shooting target is not the pedestal 13. On the other hand, if it is determined that the cross mark J is present on the shooting target (Yes in step S56), the CPU 206 determines that the shooting target is the pedestal 13.

When it is determined that it is not only the pedestal 13 (No in step S22 in FIG. 12), that is, when it is determined that the document 4 is placed on the pedestal 13, the CPU 206 sets the shooting 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 apparatus 203 performs image correction processing on the captured image according to the flowchart shown in FIG. 16 (step S25).
The CPU 206 controls the image processing apparatus 203, and the image processing apparatus 203 extracts projection parameters for performing oblique correction on the read high-resolution still image (step S71). This projection parameter indicates the relationship between the shape of the image of the document 4 and the actual shape of the document 4.

The image processing apparatus 203 further performs clipping of the object to be imaged and projection conversion to the front image in accordance with the extracted projection parameters (step S72).
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 (step S73).
The image processing apparatus 203 performs image effect processing using the extracted image effect correction parameters (step S74).

  The CPU 206 writes the corrected image data in a predetermined area in the memory 201 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 as RGB signals from the display device 202 to the projector 2 (step S75).

  When the image processing apparatus 203 performs such image correction processing, the CPU 206 writes and stores the still image that has been subjected to image correction processing by the image processing apparatus 203 in the memory 201 (step S26). The display device 202 projects a high resolution image.

  The CPU 206 returns the resolution of the camera unit 11 to the low resolution reading state again, and acquires a low resolution image (step S27).

The CPU 206 obtains the image change amount MD by the same method as that described above, and determines whether or not there is a motion in the acquired low resolution image (step S28).
If it is determined that there is no motion in the image (No in step S28), the CPU 206 obtains a low-resolution image again (step S27).
On the other hand, if it is determined that there is motion in the image (Yes in step S28), the CPU 206 resets the still time Ptime again, reads a low-resolution image, and obtains the image change amount MD (steps S14 to S16).

  If 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 another predetermined threshold value Thresh2 (Thresh1 <Thresh2), and moves the image. It is determined whether or not there is (step S29).

  If the image change amount MD is equal to or less than the threshold value Thresh2, the CPU 206 determines that there is no movement in the image (No in step S29). 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 S30).

  If the image change amount MD exceeds the threshold value Thresh2, the CPU 206 determines that the image has a motion (Yes in step S29), and sets the shooting mode to the moving image mode (step S31). Then, the CPU 206 resets the stationary time Ptime (step S14).

  On the other hand, 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 there is a motion in the image (Yes in step S30). 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 S27).

  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 is continuing (No in step S30). In this case, the CPU 206 returns to step 14.

  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.

  As described above, according to the present embodiment, the CPU 206 first detects the edge of the document edge portion discrimination area by covering the image of the mask area, and sets the detected edge amount to a preset threshold value. Compare. As a result of the comparison, if the edge amount is equal to or greater than the threshold value, the CPU 206 determines that the photographing object is the document 4. On the other hand, if the edge amount is less than the threshold value, the CPU 206 next detects the edge portion of the mask region covering the image of the document edge portion determination region, and compares the detected edge amount with a preset threshold value. . If it is determined that the threshold value is equal to or greater than the threshold, the CPU 206 determines whether or not the cross mark J is detected in the image of the shooting target. If the cross mark J is not detected, the CPU 206 determines that the object to be imaged is not the pedestal 13. On the other hand, when the cross mark is detected, the CPU 206 determines that the photographing target is the pedestal 13. The CPU 206 switches the shooting mode between the moving image mode and the still image mode based on the determination result.

Therefore, for example, when a document is not placed on the pedestal 13 such as during replacement of a sheet to be photographed, or when the position of the document 4 is greatly deviated from the photographing center, a high-definition image is photographed. , No storage and no projection. Also, it is possible to avoid wasteful shooting even when the document is a blank sheet.
Further, after the determination based on the edge amount, the detection by the detection of the cross mark J is performed to detect the edge of, for example, an out-of-focus photograph or an image drawn with only light and shade instead of a clear line. Even when a difficult sheet is placed, it is possible to accurately determine whether the photographing object is the document 4 or the pedestal 13.

  Further, when making a determination based on the edge amount, the CPU 206 detects an edge in the captured image after setting the scratch on the pedestal 13 and the surrounding area as an area not used for edge detection. Thereby, it is possible to prevent erroneous determination from occurring due to the state of the pedestal 13 (such as scratches and dirt on the pedestal).

In carrying out the present invention, various forms are conceivable and the present invention is not limited to the above embodiment.
For example, after determining the edge included in the mask area in the captured image (step S54 in FIG. 14), the amount of edge included in the portion other than the mask area in the captured image is determined (step S52). Also good. Further, if the amount of edge is greater than or equal to the specified value in the determination in step S54 (Yes in step S54), it may be determined immediately that only the pedestal is performed without searching for the cross mark J.

  Moreover, in the said embodiment, the cross mark J was marked on the surface of the base 13, and it determined by whether it was detected in the image of a to-be-photographed object. However, the mark used for the determination is not limited to a cross, and any mark that can be easily detected from an image may be used. For example, a pattern such as an alphabet is written on the pedestal 13, and it is possible to determine whether the object to be photographed is the pedestal 13 or the document 4 depending on whether or not the alphabet is detected in the photographed image.

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 all or part of the apparatus or to execute the above-described processing is stored on a flexible disk, a CD-ROM (Compact
Store it on a computer-readable recording medium such as Disk Read-Only Memory (DVD), Digital Versatile Disk (DVD), or MO (Magneto Optical disk), distribute it, install it on another computer, and operate it as the above-mentioned means Alternatively, 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 a block diagram which shows the structure of the imaging device which concerns on Embodiment 1 of this invention. It is a figure which shows a mode that the cross is drawn on the base of the imaging device shown in FIG. It is a block diagram of the document camera shown in FIG. It is explanatory drawing of the function of the image processing apparatus shown in FIG. It is explanatory drawing of each key with which the operation part shown in FIG. 3 is provided. FIG. 4 is an explanatory diagram for explaining a document edge portion discrimination area and a mask area set by a CPU shown in FIG. 3. It is explanatory drawing of the setting method of the mask area | region which masks a damage | wound. It is explanatory drawing of the detection method of an edge part. It is a figure for demonstrating the determination method of the presence or absence of the original document of CPU shown in FIG. It is a figure for demonstrating the detection method of the edge of the vertical direction in the case of a cross recognition process. It is a figure for demonstrating the detection method of the edge of the horizontal direction in the case of a cross recognition process. It is a flowchart which shows the content of the basic projection process which the imaging device shown in FIG. 1 performs. It is a flowchart which shows the content of the process which registers the damage | wound of the base which the imaging device shown in FIG. 1 performs into a mask area. It is a flowchart which shows the content of the process of the base determination which the imaging device shown in FIG. 1 performs. It is a flowchart which shows the content of the cross recognition process which the imaging device shown in FIG. 1 performs. It is a flowchart which shows the content of the image correction process which the image processing apparatus shown in FIG. 3 performs. It is explanatory drawing for demonstrating the conventional problem.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Document camera, 2 ... Projector, 3 ... Screen, 4 ... Document, 11 ... Camera part, 101 ... Optical lens apparatus, 201 ... Memory, 202 ... Display device 203... Image processing device 204... Operation unit 205 205 Program code storage device 206.

Claims (10)

In a photographing apparatus for photographing a document placed on a document table including the document table,
A photographing unit that photographs the original together with the document table at a low resolution or a high resolution;
When determining whether or not the document is placed on the document stand based on a photographed image obtained by photographing of the photographing unit, if it is determined that the document is placed on the document stand, A control unit for setting the resolution of the photographing unit to a high resolution,
The control unit includes a first determination region for determining an edge portion of the original and an edge portion of the document table outside the first determination region in a photographed image obtained by photographing of the photographing unit. A second discriminating region for discriminating an edge portion is set in advance, the number of edge portions existing in the first discriminating region covering the image of the second discriminating region is counted, and the counted first The number of edge portions in which the number of edge portions of one discrimination region is less than a preset first threshold and covers the image of the first discrimination region and is included in the second discrimination region And when the counted number of edge portions of the second determination area is less than a preset second threshold, it is determined that the document is placed on the document table.
An imaging apparatus characterized by that. The control unit counts the number of edge portions existing in the first determination region so as to cover the image of the second determination region, and the counted number of edge portions of the first determination region is preset. When the number of edges is less than the first threshold and covers the image of the first discrimination area, the number of edge portions included in the second discrimination area is counted, and the edges of the second discrimination area thus counted are counted. If the number of copies is less than a preset second threshold, it is determined that the document is placed on the document table;
The imaging apparatus according to claim 1, wherein: The document table is preliminarily marked with an identification mark at a position corresponding to the first discrimination area for discriminating an edge portion of the document.
The control unit determines an image based on the identification mark when the number of edge portions of the second region is equal to or greater than the second threshold value, and determines that the image based on the identification mark is not determined. It is determined that the document is placed on the document table.
The photographing apparatus according to claim 1 or 2, characterized in that When the control unit determines that the document is not placed on the document table, the control unit sets the resolution of the photographing unit to a low resolution.
The photographing apparatus according to any one of claims 1 to 3, wherein The control unit acquires a pixel value in the first determination region or the second determination region, and detects an edge portion based on a difference between pixel values of adjacent pixels among the acquired pixel values. Count the number of edges,
The photographing apparatus according to claim 1, wherein the photographing apparatus is characterized in that: The controller determines whether or not the image of the document is included in the captured image by determining the shape of the image by the identification mark in the captured image;
The imaging device according to claim 3. The document table is preliminarily written with a cross mark formed by line segments intersecting each other as an identification mark set with the shape,
The control unit scans pixels of the photographed image in two different directions with respect to the two line segments forming the cross mark in the photographed image, and an edge portion corresponding to the image of the cross mark is detected. Determining the shape of the cross mark image in the captured image by determining whether or not
The imaging device according to claim 6. In a photographing apparatus for photographing a document placed on a document table including the document table,
A photographing unit that photographs the original together with the document table at a low resolution or a high resolution;
When determining whether or not the document is placed on the document stand based on a photographed image obtained by photographing of the photographing unit, if it is determined that the document is placed on the document stand, A control unit for setting the resolution of the photographing unit to a high resolution,
The control unit includes a first determination region for determining an edge portion of the original and an edge portion of the document table outside the first determination region in a photographed image obtained by photographing of the photographing unit. A second discriminating region for discriminating an edge portion is set in advance, the number of edge portions existing in the first discriminating region covering the image of the second discriminating region is counted, and the counted first When the number of edge portions of one discrimination area is less than a preset first threshold, the number of edge portions included in the second discrimination area covering the image of the first discrimination area is determined. Counting, and when the counted number of edge portions of the second determination area is equal to or greater than a preset second threshold, it is determined that the document is not placed on the document table.
An imaging apparatus characterized by that. A photographing control method of a photographing device for photographing a document placed on a document table,
Obtaining a photographed image including the document table by photographing;
A second discriminating portion for discriminating an edge portion including a first discriminating region for discriminating an edge portion due to the original and an edge portion due to the document table outside the first discriminating region from the photographed image obtained by photographing. And determining the number of edge portions existing in the first determination area, covering the image of the second determination area,
When the counted number of edge portions of the first discrimination region is compared with a preset first threshold value, and the counted number of edge portions of the first discrimination region is less than the first threshold value Counting the number of edge portions included in the second discrimination area covering the image of the first discrimination area;
When the counted number of edge portions of the second discrimination region is compared with a preset second threshold value, and the counted number of edge portions of the second discrimination region is less than the second threshold value Determining that the document is placed on the document table;
When it is determined that the document is placed on the document table, the resolution of the photographing unit is set to a high resolution.
An imaging control method for an imaging apparatus. On the computer,
Photographing the document placed on the document table together with the document table;
A first discrimination region for discriminating an edge portion due to the original and an edge portion including an edge portion due to the document table outside the first discrimination region are identified in the photographed image obtained by the photographing. A procedure for counting the number of edge portions existing in the first discrimination area by covering the image of the second discrimination area in advance.
When the counted number of edge portions of the first discrimination region is compared with a preset first threshold value, and the counted number of edge portions of the first discrimination region is less than the first threshold value , A procedure for counting the number of edge portions included in the second discrimination region covering the image of the first discrimination region;
When the counted number of edge portions of the second discrimination region is compared with a preset second threshold value, and the counted number of edge portions of the second discrimination region is less than the second threshold value Is a procedure for determining that the document is placed on the document table;
A procedure for setting a resolution when shooting the document placed on the document table to a high resolution when it is determined that the document is placed on the document table;
A program for running