JP2007024736A - Method and apparatus for creating image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire optimum images of inner surfaces for inspecting the state of flaws and defects in the inner surfaces of small-diameter cylinders and holes. <P>SOLUTION: A scope head 2 using a fiber and a cylinder 1 are arranged in such a way that the center of the scope head 2 and the center of the inner surface of the cylinder 1 may be matched with each other. As moving the scope head 2 by a scope head moving device 6, the inner surface of the cylinder 1 is imaged, and information on pick-up images are captured by an image capture part 11 of an image processing device 10. A concentric image part surrounded by circles of two different radii is cut out from the captured images by a circumferential part image cutout part 12. Information on cutout images is stored in a circumferential part image storage part 13. These processings are sequentially performed. Images of the inner surface are displayed on a creation display part 14 on the basis of the stored image information. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image generation method and an image generation apparatus, and in particular, acquires an image of an inner surface of an automatic inspection apparatus that inspects a state of an inner surface of a thin tube or a cylindrical part having an inner diameter of approximately 10 mm, particularly a scratch or a defect. The present invention relates to an image generation method and an image generation apparatus suitable for the above.

  Conventionally, as this type of image capturing method for the inner surface of a cylinder, for example, as described in JP-A-8-82755, a head optical system equipped with a plane mirror and a light emitting unit for illumination is used to capture an image of the inner surface of the cylinder. There has been a method of imaging an image by scanning the inner surface of a cylinder while rotating the mechanism in the circumferential direction and forming an image on a CCD camera incorporating a linear sensor.

  In addition, as described in Japanese Patent Application Laid-Open No. 11-23477, a line sensor formed by linearly arranging CCD image sensors is inserted into a cylinder and rotated to scan the inner surface of the cylinder and display an image. A method of reproducing was also devised.

  Also, in recent years, a thin-diameter endoscope camera used for an endoscope or the like using a fiber element in a camera head portion, which has been widely used in recent years, was inserted into a cylinder and photographed with an endoscope camera. There is also a method of visually observing while looking through an image.

Japanese Patent Laid-Open No. 8-82753 Japanese Patent Laid-Open No. 11-23477

  However, in the prior art represented by the above publication, it is not technically easy to downsize the head optical mechanism and the line sensor, and the manufacturing cost is high, and practically the inside of a cylinder having a large inner diameter of 40 mm or more. However, it could not be applied to the purpose of capturing an image inside a cylinder with a small inner diameter of approximately 20 mm or less.

  In the observation method using an endoscopic camera, a wide-angle lens is usually used in the camera head so that the field of view can be as wide as possible, and the images to be captured have different lens magnifications and depths of focus at the center and the periphery. Therefore, the entire image is distorted, and the presence or absence of defects or scratches can be confirmed, but the size of the defects or scratches cannot be accurately grasped. Furthermore, the observation method using the endoscopic camera requires a lot of time and labor for holding and adjusting the position of the camera, and cannot be applied when a large amount of inspection is performed on the production line.

  As described above, conventionally, since a method for accurately imaging a cylindrical portion having a small inner diameter has not been developed, it has been impossible to automatically inspect the inside of the cylinder for scratches or defects on a production line or the like.

  In view of the above, the present invention provides a method for generating an inner surface image capable of automatically inspecting an internal image on a production line even if the cylinder has a small diameter of 20 mm or less.

  In order to achieve the above object, an inexpensive microscope using a fiber that can reduce the size of the head and a head used in an endoscope camera are used for photographing an inner surface.

  In recent years, the outer dimensions of camera heads of fiberscopes and endoscope cameras have been commercialized to around 5 mm, and are used for observation inside small-diameter holes.

  This small fiberscope or endoscope camera head is inserted into the target cylinder, moved in the axial direction, and imaged by an imaging means such as a digital camera. Only the images surrounded by are cut out and stored sequentially, and the entire image of the inner surface of the cylinder is generated as a flat image from the cut out images.

  Normally, a wide-angle lens is used at the tip of a fiberscope or endoscopic camera, and the magnification and depth of focus are different at the center and the outer periphery. It can be considered that the depth of focus is almost constant. For this reason, images taken with the center of the head coincident with the center of the inner diameter of the cylinder are composed of images of the same magnification on the circumference of the same radius.

  Now, when an image surrounded by two adjacent radii r and r + Δ is cut out from the image captured as described above, this image is a line having a width of Δ captured at the same magnification. Image information. Assuming that the minute length in the axial direction of the inner surface of the cylinder corresponding to Δ is D, when an image is taken by moving the head in the axial direction of the cylinder by D next, the image surrounded by the circumference of radius r and r + Δ is the image before the movement. An adjacent image moved by D from the image is obtained. If this adjacent image is cut out in the same way, it becomes image information of a line having a width of Δ of the same magnification. By sequentially creating and combining the image information of the lines obtained in this way, a plane image having the same magnification can be generated.

  In general, when a wide-angle lens is used, the inner surface of the cylinder is imaged from an oblique direction. Compared to the case where the image is taken from the side, the image is taken shorter than the actual size, but the image pickup device of the part where the image is cut out By taking this shooting angle into account, it is possible to correct the image and to obtain an image accuracy with no practical problem.

  In addition, the cropping width in the case of cropping an image from images captured by the imaging unit is determined in consideration of the accuracy of the image to be generated and displayed and the imaging time. If the cutout width of the image is reduced and the moving speed of the head is decreased, the resolution of the captured image can be improved and the accuracy of the image to be generated can be improved, but the imaging time of the image becomes longer.

  Fiberscopes and small endoscope cameras that use fibers are generally widely used for visually observing the inside of a thin cylinder, and the price is also low.

  Therefore, in the image generation method of the present invention, (1) when taking an image of the inner surface of the pipe, the head part of the imaging means can be moved in the pipe in the direction of the road axis. An image of the inner surface of the pipeline is taken while moving in the direction, and an inner surface image is generated and displayed from image information between a plurality of points near and near from the head part, or (2) the inner surface of the cylinder An image that captures an image of the image, and an image that captures the image captured by the imaging unit and a moving unit that moves the head unit in the axial direction by matching the center of the cylindrical inner surface with the center of the head unit of the imaging unit. Using an image capturing device composed of a processing device, the head portion is moved in the axial direction of the cylinder, the image of the inner surface of the cylinder is captured, the captured image information is captured in the image processing device, and from the captured image, Two different half Cut concentric image portion surrounded by a circle, generating display images of the inner surface from the Save and stored image information data of the image portion which is cut out, characterized in.

  The image generation apparatus of the present invention is (1) a device that captures an image of an inner surface of a pipe, and a moving unit that allows the head portion of the imaging unit to move in the pipe in the direction of the axis of the pipe. An image pickup means for picking up an image of the inner surface of the pipe line while moving the head portion in the direction of the road axis, and a display means for generating and displaying the image of the inner face from image information between a plurality of points near and near the head portion accompanying the moving shooting Or (2) movement for moving the head portion in the axial direction with the image pickup means for picking up an image of the inner surface of the cylinder and the center of the inner surface of the cylinder coincide with the center of the head portion of the image pickup means. The image of the inner surface of the cylinder was picked up by moving the head portion in the axial direction of the cylinder using an image pickup device comprising an image processing device that captures an image captured by the image pickup device and the image processing device and performs image processing. Image information processing device A computer that cuts out concentric image portions surrounded by circles having two different radii from the captured images and stores information on the cut-out image portions, and an inner image from the stored image information And display means for generating and displaying.

  The head of the imaging means applied to each image generating apparatus of the present invention may be provided with a positioning guide on the head portion so that the center of the head portion of the imaging means can move the center of the inner surface, It is preferable to attach a conical mirror for imaging the entire circumference of the side surface to the head portion.

  Furthermore, the image processing apparatus according to the present invention enables the head portion of the imaging means to move in the direction of the road axis of the pipe in the direction of the road axis when taking an image of the inner surface of the pipe. The image of the inner surface of the pipe is taken while moving the image, the image information taken by the imaging means is taken along with the moving shooting, and the concentric image portion surrounded by circles having two different radii from the taken image And processing for generating and displaying an inner surface image from the saved image information.

  According to the present invention, it is possible to accurately generate an image of the inner surface of a thin tube or cylindrical part having an inner diameter of about 10 mm, which has been difficult in the past, and the size and position of a flaw or defect can be grasped. By performing processing with a normal inspection apparatus using this image information as an input, automatic inspection on the line can be performed, and it is possible to improve the quality of products and work for workers.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a configuration diagram of an embodiment of an image generation apparatus to which the present invention is applied. 1 is a cylinder to be imaged, and 2 is a scope head for capturing an image of the inner surface of the cylinder 1. In addition, although it is a cylinder in this example, it is not limited to a tubular body such as a circular tube (or a square tube), and the shape and state of the structure forming the conduit are not limited as long as the conduit is formed. . That is, the appearance does not have to be tubular. For example, a rectangular parallelepiped or a sphere has a hole entrance into the bulk, and the passage extends into the bulk.

  An image captured by the scope head 2 is guided to the imaging camera 5 via the fiber cable 3 and the camera adapter 4 to be captured. The scope head 2 is supported and fixed to the scope head moving device 6 so as to coincide with the center of the inner diameter of the cylinder 1 as a subject, and the center of the image captured by the imaging camera 5 and the center of the cylinder 1 are always located. Configured to match. The imaging camera 5 has a built-in control device for converting the captured image into an electrical signal and connecting to another device.

  The scope head moving device 6 moves the scope head 2 in the axial direction of the cylinder 1, and the moving speed can be controlled by the speed control unit 7. Illumination light emitted from the light source device 8 is guided to the fiber cable 3 by the light guide cable 9 and supplies illumination for imaging inside the cylinder 1.

  Reference numeral 10 denotes an image processing device for capturing and processing image signals from the imaging camera 5, and internal processing includes an image capturing unit 11 for capturing an image captured by the imaging camera 5, and a circumference from the captured images. A circumferential image cutout unit 12 that cuts out the image of the image, a circumferential image storage unit 13 that stores the cut out circumferential image, and an image generation display unit 14 that generates and displays the saved image on the screen. Yes. In order to perform such processing, the imaging camera 5 transmits and receives the shutter control signal 15 and the image information signal 16, and the speed control unit 7 transmits and receives each signal of the start (or stop) signal 17.

  FIG. 2 is a diagram for explaining the content processed by the image processing apparatus 10 based on the image captured by the imaging camera 5, where (a) is the field of view of the cylinder 1 captured by the scope head 2, and (b). Is an image diagram of a captured image, and (c) is a storage image of image information.

  The operation of one cycle of FIG. 1 according to this embodiment will be described below.

  In FIG. 1, a scope head 2 is inserted into a cylinder 1 and installed so that the center of the scope head 2 and the cylinder 1 coincide. A fiber cable 3 and a camera adapter 4 for guiding an image to the imaging camera 5 are connected to the scope head 2. Further, the illumination light output from the light source device 8 is coupled to the fiber cable 3 via the light guide cable 9 to supply the illumination light to the scope head 2.

  When an activation signal 17 is input from the image processing apparatus 10 to the speed control unit 7 in this state, the scope head moving device 6 moves in the axial direction of the cylinder 1 in accordance with a specified constant speed. When the shutter control signal 15 is output from the image processing apparatus 10 while the scope head is moving, the imaging camera 5 captures an image in the cylinder 1, and the image processing apparatus 10 acquires image information 16 from the imaging camera 5. At this time, the scope head 2 is equipped with a wide-angle lens at the tip so that the field of view as wide as possible can be imaged, and the image taken with the scope head 2 inserted into the cylinder 1 is also a wide-angle image. Will be captured.

  FIG. 2A shows the field of view of the scope head 2 on the inner surface of the cylinder 1, and FIG. As shown in (b), the captured image has a concentric depth and is distorted because the magnification of the image is different between the central portion and the outer peripheral portion.

  Here, paying attention to a range corresponding to the axial length D of the cylindrical inner surface shown as the image capturing inner surface 18 in (a), this range is the inner diameter r20 indicated by the image cutout range 19 in FIG. And a range surrounded by a radius range of the outer diameter r + Δ21.

  Now, the image captured by the imaging camera 5 in this state is converted as an electrical signal of image information by the imaging camera and input to the image capturing unit 11 inside the image processing apparatus 10. The image input to the image capture unit 11 is a circumferential image cutout unit 12 that cuts out only the image of the concentric part indicated by the image cutout range 19 shown in FIG. The image cutout range 19 is surrounded by a radius range of an inner diameter r20 and an outer diameter r + Δ21. For example, image data is taken in the direction of the scanning direction 23 from the starting point 22 over the entire circumference. Thus, by cutting out images concentrically, it is possible to extract only images picked up at substantially the same magnification.

Next, the image cut out by the circumferential part image cutout unit 12 is input to the circumferential part image storage unit 13. FIG. 2C shows a storage image of the image data stored in the circumferential image storage unit 13. The image data cut out by the circumferential image cutout unit 12 has an inner diameter r shown in FIG.
It can be considered as one-dimensional information having a width d in the radius range of 20 and the outer diameter r + Δ21. Here, the width d corresponds to the width of data corresponding to the axial length D of the inner surface of interest in FIG.

  Therefore, as shown in FIG. 2C, the image cut out by the circumferential image cutout unit 12 is saved as line data corresponding to the length in the scanning direction 23 by the circumferential image storage unit 13 having a width d. It is saved with the already-completed data.

  When stored in the circumferential image storage unit 13, the shutter control signal 15 is output from the image processing device 10 at the timing when the scope head moving device 6 in FIG. 1 moves in the axial direction by the length D in the axial direction. An image is captured by the imaging camera 5. The image captured at this time is an image obtained by moving the scope head 2 by the length D in the axial direction, and the cut-out image stored at this time is the image capturing inner surface 18 (range of interest) shown in FIG. If the image information is captured, saved, and all images are captured and then combined, image information without overlapping images can be obtained.

  Thereafter, the same processing is repeated while moving the scope head moving device 6 in the same manner, whereby an image can be captured and stored along the axial direction of the cylinder 1. As a result, image information with constant magnification and no distortion can be obtained over the entire length of the cylinder 1. The image stored in this way can display the inner surface of the cylinder as a planar image on the image generation / display unit 14 of the image processing apparatus 10.

  In addition, if the start position of image capture and the position inside the cylinder are defined, the coordinates (position) and size of scratches and defects inside the cylinder can be quantified. Can be done.

  The radial width of the image cutout range of the present embodiment can be arbitrarily set according to the image resolution of the scope head and imaging camera used, the distortion rate of the scope head, and the resolution of the image to be generated. Generally, the resolution of the generated image can be increased by reducing the image cropping width and reducing the moving speed of the scope head 2.

  In the above embodiment, an example is shown in which a scope head using a fiber is used to image the inner surface of a cylinder. However, any small camera that can be inserted into a cylinder can be applied to an endoscope camera.

  In addition, although the camera head moving device has described the method of imaging while moving at a constant speed, a method of operating the scope head moving device 6 in a pattern of repeatedly starting and stopping according to the timing of shooting may be adopted.

  In addition, this method can be applied not only to a straight cylinder but also to imaging inside a curved cylinder. Therefore, by attaching the positioning guide 24 shown in FIG. 3 to the distal end portion of the scope head 2, the scope head 2 can always move the center of the cylinder 1 when moving the camera head in the axial direction. Thus, the same effects as in the embodiment can be obtained.

  In general, an image captured with a wide-angle lens uses an image of a side surface captured from an oblique direction. Therefore, an image to be generated needs to be corrected in accordance with the imaging angle. In order to eliminate this influence, a more accurate generated image can be obtained by imaging using a conical mirror 25 as shown in FIG. 4 so that only the side surface can be imaged directly instead of a wide-angle lens. Can do. The conical mirror 25 is held by a transparent cylindrical body 26 made of plastic or the like, and is used by being attached to the tip of the scope head 2.

  As described above, the apparatus and method of this embodiment can provide a cost-effective method by using an inexpensive imaging means without using a complicated optical system. Furthermore, if a positioning guide is provided so that the head position of the imaging means moves while contacting the inner surface of the cylinder so that the center of the inner surface of the cylinder is held, not only a straight cylindrical part but also a curved pipe or cylinder In contrast, an image inside the cylinder can be taken. For example, only the image of the side portion is used in the full-field image captured by the wide-angle lens. Then, by adding a unit such as a conical mirror for imaging only the side surface of the cylinder, it is possible to accurately capture only the image of the required side surface, and improve the resolution of the generated image. Can do. In addition, the image information captured by the imaging device is captured, and a concentric image portion surrounded by two different radius circles is extracted from the captured image, and the information of the extracted image portion is saved and stored. The processing for generating and displaying the inner surface image from the image information may be performed by software processing, but by using a dedicated image processing board, processing can be performed at higher speed.

It is a schematic block diagram of one Example for producing | generating the image of the cylindrical inner surface which concerns on this invention. It is an image figure of the image imaged with the scope head inserted in the cylinder at the time of using the Example apparatus of this invention, and the image information captured and preserve | saved. It is a relationship explanatory view showing a guide of a scope head attached so that the center of the scope head of the imaging camera and the center of the cylinder coincide with each other when the embodiment device of the present invention is used. It is a related explanatory drawing of the head which attached the conical mirror for imaging only the side surface of a cylindrical inner surface at the time of using the Example apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylinder, 2 ... Scope head, 3 ... Fiber cable, 4 ... Camera adapter, 5 ... Imaging camera, 6 ... Scope head moving device, 7 ... Speed control unit, 8 ... Light source device, 9 ... Light guide cable, 10 ... Image processing apparatus 11... Image capture unit 12. Circumference image cutout unit 13. Circumference image storage unit 14. Image generation display unit 15. Shutter control signal 16. Image information signal 17. Signal 18, inner surface of image capturing 19, image cropping range 20, inner diameter r, 21 outer shape r + Δ, 22 starting point, 23 scanning direction, 24 guide, 25 conical mirror, 26 transparent cylinder.

Claims (7)

  When taking an image of the inner surface of the pipeline, the head portion of the imaging means is movable in the direction of the road axis of the pipeline, and the image of the inner surface of the pipeline is moved while moving the head portion in the direction of the road axis. And generating and displaying an image of the inner surface from image information between a plurality of points near and near from the head unit, which is associated with moving shooting.   The image pickup means for picking up an image of the inner surface of the cylinder, the moving means for moving the head portion in the axial direction by matching the center of the inner surface of the cylinder and the center of the head portion of the image pickup means and the image picked up by the image pickup means are processed. Using an image capturing device composed of an image processing device to perform, the image of the inner surface of the cylinder is captured while moving the head portion in the axial direction of the cylinder, the captured image information is captured in the image processing device, and the captured image of the captured image is captured. An image characterized in that a concentric image portion surrounded by circles having two different radii is cut out from the inside, the information of the cut out image portion is saved, and an inner image is generated and displayed from the saved image information. Generation method.   An apparatus that captures an image of an inner surface of a pipeline, and a moving unit that allows the head unit of the imaging unit to move in the pipeline in the direction of the road axis, and the head unit is moved in the direction of the road axis. In addition, the image processing apparatus includes: an imaging unit that captures an image of the inner surface of the duct; and a display unit that generates and displays an image of the inner surface from image information between a plurality of points near and near the head unit associated with moving shooting. Image generation device.   The image pickup means for picking up an image of the inner surface of the cylinder, the moving means for moving the head portion in the axial direction by matching the center of the inner surface of the cylinder and the center of the head portion of the image pickup means and the image picked up by the image pickup means are processed. An image pickup device comprising an image processing device to be used is used to pick up an image of the inner surface of the cylinder while moving the head portion in the axial direction of the cylinder, and the acquired image information is taken into the image processing device. A computer that cuts out concentric image portions surrounded by circles having two different radii, stores information on the cut out image portions, and display means for generating and displaying an inner surface image from the stored image information. An image generation apparatus comprising:   5. The imaging means applied to the image generation apparatus according to claim 3, wherein a positioning guide is provided on the head portion so that a center of the head portion of the imaging means can move on a center of the inner surface. head.   5. The head of the imaging means applied to the image generating apparatus according to claim 3 or 4, wherein a conical mirror for imaging the entire circumference of the side surface is attached to the head portion of the imaging means. When taking an image of the inner surface of the pipe, the head of the imaging means is movable in the direction of the road axis of the pipe, and the image of the inner surface of the pipe is moved while moving the head in the direction of the road. The image information captured by the image capturing means is captured along with moving imaging, and concentric image portions surrounded by circles having two different radii are extracted from the captured images, and information on the extracted image portions is captured. Is an image processing apparatus that performs processing for generating and displaying an inner surface image from the stored image information.

Images