JP2006279828A - Document camera apparatus and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a document camera apparatus which is capable of easily obtaining high-quality and beautiful still picture data with no hot spot without being enlarged as a whole. <P>SOLUTION: The document camera apparatus 10 includes an original platen 15, a supporting pole 17 supported on the original platen 15 so as to swing, a camera mount 13 and an illuminator 21 in an upper part of the supporting pole 17 and fixes a imaging device 11 on the camera amount 13 so that the imaging device 11 can be disposed near the illuminator 21. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a document camera that captures and records a subject on a document table with an imaging device and projects the image.

2. Description of the Related Art Today, a document camera device is used that places a document, a photograph, or an article on a document table, picks up an image with an image pickup device, and projects the image using a projector or the like.
With this document camera device, when a document such as a photograph is imaged, light from the document illumination device is reflected on the surface of the document so that it is not reflected in the image of the subject imaged by the imaging device, and a beautiful image is recorded. Since there is a need to be able to project, there is an apparatus in which an illuminating device is installed at a position left and right away from the imaging device and illuminates illumination light from a side to a subject such as a document (for example, Patent Document 1).

  In order to make the document camera device compact, it is possible to devise the arm structure that connects the document table, the illumination device, and the image pickup device, and attach a filter to the illumination device or the image pickup device to take a beautiful image as much as possible. There is also what makes it possible (for example, patent document 2).

Further, in a document camera apparatus, in order to make it easy to see a document or a photograph, it is common to image the document from the front direction by capturing the document table from the center vertical direction of the document table. Incorporating a trapezoidal distortion correction circuit and correcting the image captured by the imaging device from an oblique direction on the document table as if it were viewed from the front of the subject, so that a subject such as a photograph can be imaged from the oblique direction when replacing a document Some that facilitate handling have been proposed (for example, Patent Document 3).
JP 2003-333776 A JP 2003-153041 A JP 2005-005920 A

  As described above, the document camera apparatus can capture a subject on a platen and record image data and project an image based on the image data. In some cases, the lighting device is reflected to generate a hot spot, which deteriorates the image quality.

  In order to prevent hot spots from occurring, if the lighting device is installed at a position away from the imaging device or if a process such as illuminating a subject from the side by indirect lighting is performed, the entire document camera device becomes large, In addition, there is a disadvantage that becomes complicated.

  The present invention provides a document camera apparatus that can obtain beautiful still image data with high image quality without a hot spot by synthesizing a plurality of times of imaging data without increasing the size of the entire document camera apparatus. To do.

The present invention has a document table (15) and a support column (17) pivotally supported by the document table (15), and a camera mounting table (13) above the support column (17). And a document camera device (10) having an illuminating device (21), wherein the imaging device (21) is fixed to the camera mount (13) so as to dispose the imaging device (11) in the vicinity of the illuminating device (21). To do.
The imaging device (11) is a digital camera having an image correction function such as a keystone correction.

  In addition, the image forming method according to the present invention images a subject from a plurality of locations while maintaining a predetermined positional relationship between the imaging device (11) and the illumination device (21), and image data other than the image data captured from directly above is obtained. After correction to image data picked up from the front, each drawing data is synthesized into one piece of image data.

Note that imaging may be performed twice, ie, directly above the document table (15) and in an oblique direction.
When imaging the same subject multiple times, the center of the document table (15) is preferably the center of the field of view of the imaging device (11), and the distance from the center of the document table (15) is always constant. It is preferable.

  Since the present invention is a document camera device having an illumination device and an imaging device on the upper part of a support column that is pivotally supported on a document table, by imaging the same subject by swinging the support column, This is an apparatus that can obtain images of the same subject with different hot spot positions by the illumination device, and can easily obtain an image in which the hot spots are eliminated by combining the images.

  In addition, the image forming method according to the present invention captures a subject from a plurality of locations and synthesizes each drawing data into one piece of image data. Therefore, it is possible to easily obtain an image from which hot spots are erased. It can be done.

  In the best mode of the present invention, an illuminating device 21 and an imaging device 11 are arranged on an upper portion of a support column 17 that is pivotally supported on a document table 15 so that a subject is positioned at the center of the visual field of the imaging device 11. Then, the subject is imaged from the front position of the subject, and the same subject is taken again from an oblique direction with this point as the center of the field of view without changing the distance from the center of the field of view on the document table 15. After the image is captured and the image from the oblique direction is corrected to the image seen from the front, the subject in the image captured from the front is matched with the size of the subject in the corrected image.

  After that, the hot spot 29 in the image captured from the front is detected and the image data of the hot spot 29 and its surroundings are replaced with the image data of the same region in the image captured from the oblique direction and corrected to the same size. is there.

  As shown in FIGS. 1 and 2, the document camera device 10 according to the present invention has a support column 17 rotatably attached to a document table 15 by a support shaft 18, and an illumination device 21 is provided at the upper end of the support column 17. Is provided on the lower surface, and a digital camera using a solid-state imaging device such as a CCD is fixed to the camera mounting base 13 as the imaging device 11.

  The support column 17 can be tilted and swung about the support shaft 18, and the vertical position and tilted positions of 15 degrees, 30 degrees, and 45 degrees to the left and right with the upper surface position of the document table 15 as the swing center. And a notch and a stopper member (not shown).

  Further, as shown in FIG. 3, the digital camera as the image pickup apparatus 11 includes a lens optical system 51, an image pickup element 55, a DRAM 77 and a VRAM 87, and a control unit 81. Further, the image pickup apparatus 11 A display unit 91 for forming a monitor screen on the upper surface of the image sensor, and an image of the subject placed on the document table 15 is formed on the image sensor 55 by the lens optical system 51 driven by the lens driving device 63. Is.

In the imaging mode, the imaging device 55 is scanned and driven by the timing generator 61 and the vertical driver 63, and outputs one screen of photoelectric conversion output corresponding to the optical image formed at regular intervals.
The photoelectric conversion output is appropriately gain-adjusted for each primary color component of RGB in an analog signal state, then sampled and held by the sample hold circuit 57 and converted into a digital signal by the analog / digital conversion circuit 59.

The digital signal is subjected to color process processing including pixel interpolation processing and gamma correction processing by the color process circuit 71 to generate a luminance signal and a color difference signal which are digital signals.
Further, the luminance signal and the color difference signal are input to the direct memory access controller 73, and are written to the buffer in the direct memory access controller 73 by the composite synchronization signal, the write control signal, and the clock signal from the color process circuit 71, and the DRAM interface. The data is transferred via DMA to a DRAM 77 serving as a buffer memory.

  The control unit 81 includes a CPU, a ROM that stores an operation program, a RAM that is used as a work memory, and the like. The control unit 81 controls the operation of the entire imaging apparatus 11, and after the DMA transfer to the DRAM 77 is completed, the luminance signal The color difference signal is read from the DRAM 77 and written to the VRAM 87 via the VRAM controller 85.

The digital video encoder 89 periodically reads the luminance signal and color difference signal written in the VRAM 87 via the VRAM controller 85, generates a video signal, and outputs the video signal to the display unit 91.
Therefore, in the imaging mode, the light image formed on the imaging element 55 can be displayed on the display unit 91 in real time and monitored on the monitor screen.

When the shutter key of the key input unit 83 is operated, a trigger signal is input to the control unit 81, and the control unit 81 performs image data recording and storage processing.
In this recording / storing process, immediately after the completion of the DMA transfer in which the luminance signal and the color difference signal for one screen are written to the DRAM 77, the path from the image sensor 55 to the DRAM 77 is interrupted, and the signal for one screen written to the DRAM 77 is received. Each component is read in units of basic blocks and written to the JPEG circuit 93.

In the JPEG circuit 93, data compression is performed by processing such as adaptive discrete cosine transform and Huffman coding, and the compressed data for one screen is stored as one file in the flash memory 95 which is a nonvolatile memory.
At this time, in addition to the file name, data such as the zoom magnification, the data size, and the imaging condition are recorded as the header information of the file.

  In addition, the flash memory 95 is enclosed in a memory card that is removable as a recording medium of the image pickup apparatus 11, is built in the image pickup apparatus 11, and further uses both a memory card and a built-in memory. and so on.

When the compressed luminance signal and color difference signal for one screen are recorded in the flash memory 95, the control unit 81 restarts the operation of the path from the image sensor 55 to the DRAM 77, and the image from the image sensor 55 to the DRAM 77. The data is stored, the image data is written into the VRAM 87, and the real-time monitor image is displayed again on the display unit 91.
In addition to the shutter key, the key input unit 83 includes a power key, a mode switch, a menu key, a cross key, and the like.

  In the playback mode, the control unit 81 selects and reads out the image data recorded in the flash memory 95 based on the key operation signal input from the key input unit 83, and the JPEG circuit 93 performs data compression in the imaging mode. The image data is decompressed by a procedure that is completely opposite to the procedure described above, the decompressed image data is held in the DRAM 77 via the DRAM interface 75, and the content held in the DRAM 77 is written to the VRAM 87 via the VRAM controller 85, and the digital video encoder 89 Is displayed on the display unit 91.

  The image data recorded in the flash memory 95 and the data written in the DRAM 77 are sent to an external device connected to the USB connector 99 via the USB interface 97.

  When the subject placed on the document table 15 is imaged by the imaging device 11, the illumination device 21 is turned on at the vertical position (B) shown in FIG. The image is placed at a predetermined position directly below the lens of the imaging device 11, and the first image is recorded by operating the shutter key in the hot spot erasing mode, and the support column 17 is tilted to the right or left, for example, tilted to the right. The second image is recorded at the right inclined position (C) shown in FIG.

  As described above, when the first image recording and the second image recording for imaging the same subject from the position directly above and obliquely are performed, in the hot spot erasing mode, as shown in FIG. After S101) and the second image recording (S103), the second image correction process (S110) for correcting the second image to the state seen from the front and the hot spot area of the first image are corrected with the image data of the second image The image composition processing (S120) is performed, and the corrected image recording (S131) for storing the corrected image data and the display processing (S135) for enabling display of the corrected image are performed.

  That is, the first image picked up from the front of the subject is picked up from a right inclined position (C), for example, as shown in FIG. As shown in FIG. 5C, the image is picked up as a quadrilateral whose right side is wide and distorted.

  In the first image captured from the front, a hot spot 29 by the illumination device 21 is generated at the center line of the subject, and in the second image, the hot spot 29 is located at the left side near the imaging device 11 and the illumination device 21. It will occur.

  Then, the second image correction process (S110) for performing trapezoidal distortion correction and subject size adjustment for correcting the second image into a rectangular image of the upper body as viewed from the front, as shown in FIG. Edge image creation (S201) for converting to an edge image based on the luminance signal of the image is performed, straight line detection (S203) for detecting a straight line portion is performed, and the intersection of straight lines is obtained to identify the maximum quadrilateral in the image. The maximum rectangle is selected (S205), the coordinate calculation (S207) is performed to obtain the coordinates of the four corners where the maximum rectangle is a rectangle from the front, and the correction value is calculated to correct the rectangle to a rectangle (S209). Is to do.

  Further, a first edge image is created to convert the first image into an edge image (S211), a maximum rectangle is selected (S213) for specifying the maximum rectangle in the first edge image, and the coordinates of the four corners of the rectangle are determined. The calculated coordinates are calculated (S215).

  Then, the coordinate values of the rectangle calculated in the coordinate calculation (S207) in the trapezoidal distortion correction for the second image are compared with the coordinates of the four corners of the rectangle searched based on the first image, and the four corners calculated by the trapezoidal distortion correction are compared. Interpolation is performed in which coordinate values are corrected to match the coordinates of the four corners of the retrieved rectangle (S217), and pixel interpolation is performed on the image data so as to match the four corners of the trapezoidal quadrilateral of the second image with the corrected coordinate values. Processing (S221) is performed.

  Therefore, the second image that has been distorted into a trapezoid is made rectangular by trapezoidal distortion correction, and subject size adjustment is performed by matching the size of the first image and subject image by coordinate alignment of the four corners. As shown in (C ′) of FIG. 7, it is possible to obtain a second image corrected to a quadrilateral that matches the coordinates of the four corners of the rectangle of the first image.

  Further, in the image composition process (S110) for compositing the first image and the second image, as shown in FIG. 8, the first image hot spot detection (S310) for determining the hot spot area in the first image is performed, Further, the zoom information is read (S321) to determine the cutout region 31 (S325).

  In this hot spot detection (S310), the luminance signal level is sequentially determined from the first column in the first row of the inspection area. First, as shown in FIG. 9, it is determined whether or not the luminance is the highest (S401). If the maximum luminance is not the highest luminance, it is determined whether the previous luminance was the highest luminance (S403), and the next pixel data is determined whether it is the highest luminance (S401). Data search is performed.

  In the case of the maximum luminance, coordinate recording (S405) for storing the coordinates of this pixel is performed, and it is determined whether or not the previous luminance was the highest luminance (S403). The start point storage (S409) stored as the start point of the line is performed, and if the previous highest brightness is obtained, the process returns to the highest brightness judgment (S401) for the next pixel.

  If the highest brightness is not determined in the highest brightness determination (S401) and the previous time was the highest brightness, end point storage (S411) for storing the coordinates as the end point of the white line is performed. Is determined to include the center line coordinates (S413). If the center line coordinates are not included, the white line data is discarded (S415) and the process returns to the determination of the maximum luminance for the next pixel (S401). It is.

  If this white line includes the center line coordinate, it is determined whether the previous line is continuous with the previous line (S421), which is a determination as to whether or not the white line exists at this coordinate position in the previous line. If the white line length of the previous line is added to the length of the white line of the previous line (S423), the length of the white line is stored as a new area if it is not continuous with the white line of the previous line. The new area to be processed (S425) is performed.

  Then, a final position determination (S427) is performed to determine whether or not the pixel is in the last column of the row, and if it is not the final position, the process returns to the determination of the highest luminance of the next pixel (S401). If it is not the final line, the final line determination (S429) is performed, and the process returns to the highest luminance determination (S401) of the pixel in the first column of the next row.

In addition, after the determination of the maximum luminance of each pixel up to the last column of the last row (S401), when there are a plurality of continuous white lines, an area comparison (S431) is performed to determine the one with the largest area as the hot spot 29. The maximum area is determined (S435).
Thus, after hot spot detection (S310) is performed, the cutout region 31 is determined (S325) based on the zoom information.

  In this document camera device, since the distance between the image pickup device 11 and the document table 15 is kept constant by the support column 17, the range in which the illumination device 21 is reflected in a subject such as a photograph is determined, and the image pickup device is determined by the zoom magnification. Since the size of the hot spot 29 on the screen is determined once the field of view range of 11 is determined, the position of the hot spot 29 and the area in which the color of the object around it is determined in advance by the zoom magnification As shown in FIG. 10, a hot spot 29 and a cutout region 31 including its periphery are determined.

  When the cutout area 31 of the first image is determined, the second image data reading (S331) is performed to read the image data of the area 31 ′ of the modified second image C ′ of the area corresponding to this area. A second image data synthesis (S335) is performed in which the image data of the image is replaced with the data of the cutout region 31 of the first image data to create an image without the hot spot 29.

  In the hot spot deletion process after the first image recording and the second image recording, the data of the first image and the second image recorded in the flash memory 95 by the control unit 81 is decompressed by the JPEG circuit 93. The decompressed first image data and second image data are written into the DRAM 77 for processing, and new image data obtained by synthesizing the second image data is created in the DRAM 77 and newly flashed through the JPEG circuit 93. When recording in the memory 95, or adding information such as trapezoidal distortion correction information and interpolation information by subject size adjustment to the second image data, the header information of the second image file is added, and information about the cutout area in the first image is added to the first image data. In addition to the header information of the image file, the data of the first image and the second image may be left.

  In this way, if new image data from which the hot spot 29 is erased is recorded or two screen data to be modified are recorded so as to remain, a high-quality beautiful image without the hot spot 29 can be displayed on the display unit. The image can be projected on the screen of an external computer connected to the USB connector 99 or a projector.

In the above embodiment, the first image recording is taken from the front of the subject. However, as another embodiment, both the first image recording and the second image recording are taken from the same subject in an oblique direction to obtain a hot spot. 29 is to be erased.
In the second embodiment, the same subject is imaged from the left inclined position A and the right inclined position C of the support pillar 17 shown in FIG. ), An image whose left side width is distorted more than the right side and an image whose right side width is distorted more than the left side as shown in (C) are obtained.

  Accordingly, the trapezoidal distortion correction processing is performed on the first image and the second image, and the subject size is adjusted, and as shown in FIG. 12, an edge image is created based on the first image (S501). Then, the intersection of the straight line and the straight line is obtained by the straight line detection (S503), the maximum quadrangle is selected (S505), the coordinate values are calculated to correct the four corners of the quadrangle to the four corners of the rectangle (S509), and it is determined whether or not it is the first time. If it is the first time in (S511), an interpolation process (S513) is performed to correct the first image to a rectangular state viewed from the front, and image data recording (S515) for storing the corrected first image data is performed. Is what you do.

  Similarly, in the second image, an edge image is created (S501) to detect a straight line (S503), select a maximum rectangle (S505), and calculate a coordinate value (S509) to determine whether it is the first time. Since this is the second time in (S511), the coordinate values of the four corners of the rectangle obtained by the coordinate value calculation (S509) for the second image are matched with the coordinate values of the four corners of the rectangle obtained by the coordinate value calculation (S509) for the first image. Coordinate value correction (S521) is performed, and the second image data corrected by performing an interpolation process (S523) for correcting the second image to a rectangular state viewed from the front according to the corrected coordinate values of the four corners. The stored image data is recorded (S525).

  By this trapezoidal distortion correction and subject size adjustment, the first image and the second image have the same size and are rectangular as seen from the front, as shown in FIG. 14 (A ′) and (C ′). This can be a corrected image.

  When the first image and the second image are combined, the hot spot 29 in the first image and the second image is detected. As shown in FIG. 13, the hot spot 29 in the first image is detected. The first image hot spot detection (S610) is performed, and the center coordinate storage (S615) for calculating and storing the center coordinate of the hot spot 29 is performed.

  In the first image hot spot detection (S610), the continuity of pixels with the highest luminance is detected over the entire area of the first image, and the area of white lines that are continuous in the vertical and horizontal directions, which is the maximum area, is used as the hot spot 29.

  Similarly, the second image hot spot detection (S620) for detecting the hot spot 29 by detecting the continuity of the highest luminance in the entire area of the second image and calculating the center coordinates of the hot spot 29 in the second image. The center coordinate is stored (S625), and the intermediate line determination (S631) is performed to obtain the intermediate line 32 located at the center between the center of the hot spot 29 in the first image and the center of the hot spot 29 in the second image. The first image and the second image are cut by the intermediate line 32, and the image of the subject from which the hot spot 29 is deleted is synthesized as shown in FIG.

  With this method of imaging the subject from the left and right diagonal directions, it is possible to obtain a beautiful image as a whole without having the hot spot 29. In the method of imaging from the front and diagonal directions described above, the center portion However, even if it has a low-quality part compared to other parts, it is possible to obtain a high-quality and beautiful image as the whole image.

Furthermore, as another embodiment, the same subject is imaged from the front and the left and right of the subject, and as shown in FIG. 15, the first image (A), the second image (B), and the third image (C) May be recorded.
In this case, the first image (A) and the third image (C) are subjected to trapezoidal distortion correction and subject size adjustment processing and synthesized as image data having the same size as the second image (B). In addition to automatic erasing of the hot spot 29, it is possible to select and synthesize a portion having a good imaging state.

  As described above, the imaging device 11 uses a digital camera having functions of trapezoidal distortion correction and image synthesis, performs edge extraction processing from image data to obtain a straight line, and further obtains an intersection of the straight lines in the image. The four corners of the largest quadrilateral are specified, the lengths of the long side and the short side are determined with reference to the long side of the two opposing sides, and the image is corrected to a rectangular image by enlargement interpolation processing.

  Thereafter, a document size matching process is performed to correct the rectangular images A and C to the same size as the rectangular image B, hot spot detection is performed from the image data of the image B, and the hot spot 29 and surrounding image data are obtained. An image composition process for replacing the image data of the image A or the image C in the same region is performed.

  Therefore, it is possible to record and display a high-quality and beautiful video by performing the image composition process (S130) for deleting the hot spot 29 and performing the display process (S140) for projecting the composite image.

  In addition, it is possible to image a subject such as a photograph or a document placed on the document table 15 from the front with the lens position of the image pickup device 11 being directly above the center of the document table 15, and the support column 17 is swung. At this time, the support column 17 is attached to the document table 15 so that the distance between the center of the document table 15 and the imaging device 11 does not change, and the center of the subject such as a rectangular standard document is placed on the upper surface of the document table 15. It is preferable to provide a guide line or the like that facilitates placing the subject on the document table 15 in accordance with the center of the table 15.

  It should be noted that front shot correction processing such as trapezoidal distortion correction is also performed on an image captured with the support pillar 17 vertical, and imaging is possible even when the subject center such as a document is not located directly under the lens of the imaging device 11, It may be easy to install or replace a subject such as a document on the document table 15.

  Furthermore, the subject is not limited to a planar area such as a poster, a photograph, or a manuscript, and a three-dimensional subject can be imaged. Front shooting correction (S110), size adjustment (S120), and image composition processing (S130) This processing function is not limited to being built in the imaging device 11 fixed to the camera mounting base 13, but transfers image data from the imaging device 11 fixed to the camera mounting base 13 to another computer connected by a USB cable or the like. In some cases, processing is performed.

The side view which shows an example of the document camera apparatus which concerns on this invention. The front view which shows an example of the document camera apparatus which concerns on this invention. 1 is a diagram illustrating an example of a circuit block of an imaging device in a document camera device according to the present invention. The flowchart figure which shows the process sequence of this invention. The figure which shows typically an example of the image data imaged with the document camera apparatus which concerns on this invention. The flowchart figure which shows the example of the trapezoid distortion correction process of the image composition process in this invention. The figure which shows typically the image data which performed the trapezoid distortion correction process in this invention. The flowchart figure which shows the process sequence of the image composition process in this invention. The flowchart figure which shows the procedure of the hot spot detection process of the image synthesis process in this invention. The figure which shows typically the image data of the image composition process in this invention. The figure which shows typically the image in 2nd Example of the image composition process in this invention. The flowchart figure which shows the trapezoid correction process sequence of the image composition process in 2nd Example of this invention. The flowchart figure which shows the process sequence of the image composition process in 2nd Example of this invention. The figure which shows typically the 2nd Example of the image composition process in this invention. The figure which shows typically the other example of the image data imaged with the document camera apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Document camera apparatus 11 Imaging apparatus 13 Camera mounting stand 15 Document stand 17 Support pillar 18 Support axis 29 Hot spot 31 Deletion area 32 Middle line 51 Lens optical system 53 Lens drive device 55 Imaging element 57 Sample hold circuit 59 Analog digital conversion circuit 61 Timing generator 63 Vertical driver 71 Color process circuit 73 Direct memory access controller 75 DRAM interface 77 DRAM
81 Control unit 83 Key input unit 85 VRAM controller 87 VRAM
89 Digital video encoder 91 Display unit 93 JPEG circuit 95 Flash memory 97 USB interface 99 USB connector

Claims (6)

  The document table, a support column that is pivotally supported by the document table, a camera mounting base and an illumination device above the support column, and the imaging device is disposed in the vicinity of the illumination device A document camera device characterized in that an imaging device is fixed to a mounting base.   The document camera apparatus according to claim 1, wherein the imaging apparatus has an image correction function such as trapezoid correction and a function of combining a plurality of image data.   The same subject placed on the document table is imaged from a plurality of locations while maintaining the imaging device and the illumination device in a predetermined positional relationship, and image data other than the image data captured from directly above is corrected to image data captured from the front. Thereafter, each image data is synthesized into one piece of image data.   The image forming method according to claim 3, wherein the imaging of the same subject is performed twice, that is, directly above the document table and in an oblique direction.   5. The image forming method according to claim 3, wherein the same subject is imaged by setting a center of the document table as a center of a field of view of the imaging apparatus.   6. The image according to claim 3, wherein when the same subject placed on the document table is imaged a plurality of times, the distance from the center of the document table is always constant. Forming method.

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