Image analysis – Image transformation or preprocessing – Combining image portions
Reexamination Certificate
1998-06-24
2001-04-10
Tran, Phuoc (Department: 2721)
Image analysis
Image transformation or preprocessing
Combining image portions
C382S167000, C382S254000, C382S255000, C382S274000, C382S275000, C348S584000, C348S598000, C358S450000
Reexamination Certificate
active
06215914
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a picture processing apparatus aiming at processing a plurality of pictures. In particular, the invention relates to a picture processing apparatus for detecting a mismatch of images within two pictures as well as to a picture processing apparatus for obtaining a composite picture high resolution or a picture of wide angle/wide range having a greater number of pixels than a picture obtained by an image pickup device by one time of image pickup operation. The invention also relates to a picture processing apparatus for compensating a density value of pixels of each picture so that the overall lightness of two or more pictures is equalized, and for correctly compensating color tone of the composite picture.
2. Description of Related Art
A picture processing apparatus used as a so-called scanner is provided with a one-dimensional image pickup device like a CCD line sensor in which a plurality of photo-receiving areas are arrayed in a row. This picture processing apparatus produces an output picture, by picking up images of a subject at a plurality of positions while moving the image pickup device with respect to the subject in a direction orthogonal to a direction in which the photo-receiving areas are arrayed on a two-dimensional plane. The apparatus then composites the pictures obtained by the respective image pickup operations such that they are arrayed on the two-dimensional plane in a relationship of a position identical to a position of the image pickup device in picking up each image, to produce a single output picture. As compared to a picture obtained directly by the image pickup device, though the number of pixels arrayed in the same direction as a moving direction of the image pickup device increases in the picture obtained by this apparatus, the number of pixels in a direction orthogonal to the moving direction is no different. As a method for increasing the number of pixels of the picture in the above-mentioned orthogonal direction, there has been a method of compositing the plurality of above-mentioned output pictures by arraying along the orthogonal direction.
As a first prior art technology using the above-mentioned method, there may be cited a method disclosed in Japanese Unexamined Patent Publication JP-A 63-64180 (1988). According to an apparatus using the picture image compositing method disclosed in this publication, a one-dimensional image pickup device is provided within a manually movable hand scanner. According to this method, at first, an original picture to be input is divided into areas of a size readable by one time of scan by using the hand scanner, and a picture of each area is obtained by picking up its image by moving the hand scanner along a center axial line of the areas with the scanner contacted on the surface of the original picture. The picture of each area is equivalent to the output picture of the above-mentioned apparatus using the one-dimensional image pickup device and each image has an overlapping area where the same part of the original picture has been read. Next, the overlapping areas of the respective areas are matched by way of the template matching method to find a positional mismatch of the images having the same shape and the same distribution of brightness between the respective images. Finally, based on the positional mismatch of the images, each picture is moved in parallel and superimposed so that those images overlap to obtain a composite picture image.
In this picture image compositing method, since an operator of the apparatus manually moves the hand scanner containing the image pickup device, an unintentional movement of the hands of the operator may be applied to the hand scanner when the scanner is moved. A relative position between the image pickup device within the hand scanner and the center axial line of the above-mentioned areas of the original picture to be input may also incline for the same reason. Further, a pair of rollers are provided within a part of the hand scanner where it contacts with the original picture so that the hand scanner moves smoothly on the surface of the original picture, and the moving speed of the hand scanner may differ between parts thereof near one roller and near the other roller, when the smoothness of the pair of rollers is different from each other. When these things happen, a distortion of an image including a mismatch of the image in a direction different from a direction of the parallel movement and a partial compression of the image occurs within the pictures. Because the images of the subject in the plurality of pictures having such a distortion are not smoothly joined just by horizontally moving the pictures, the image distorts in the composited picture.
In order to compensate this mismatch, the applicant of the present invention has proposed, in Japanese Unexamined Patent Publication JP-A 5-260264 (1993), a technology for obtaining an output picture composed of a more number of pixels than a number of photo-receiving areas of an image pickup device by using a two-dimensional image pickup device in which photo-receiving areas are arrayed in a matrix. This technology will be explained below as a second prior art technology. According to a picture processing apparatus disclosed in this publication, an operator holds means for inputting an image, i.e. a so-called CCD imaging apparatus, and shoots a subject while horizontally moving the imaging apparatus at a position distant from the subject by a predetermined distance to obtain a plurality of pictures. A processing circuit within the above-mentioned picture processing apparatus matches a new picture with a composite picture by way of, e.g., the block matching method every time when the new picture is obtained to find a positional mismatch of the same image within both the pictures. Next, based on this mismatch, the new picture is transformed and the transformed image is finally composited with the composite picture to obtain a new composite picture.
Because the image inputting means of this picture processing apparatus is supported only by the hands of the operator of the apparatus and is held in air, a relative position between the subject and the image pickup device is liable to shift. Due to that, a distortion of the image including a mismatch of the image in a direction other than a direction in which the image inputting means is moved horizontally, an inclination of the image and a different magnification factor, occurs between the images in the two pictures to be composited. Although the picture processing apparatus composites the pictures while compensating this distortion of the image when compositing, all distortions may not be compensated and some distortion remain due to, e.g., a matching error and a compensation error which will be described later. Further, arithmetic processing for this compensation is complicated and a processing amount of the compensation increases.
As a third prior art technology, there may be cited a technology disclosed in Japanese Unexamined Patent Publication JP-A 4-314263 (1992). A picture processing apparatus disclosed in this publication first extracts features such as an edge of an image from data sets of a plurality of pictures to be composited which have been input from a scanner. Then, it obtains a composite picture by generating address information for joining the picture data sets based on the features and by joining the plurality of data sets at positions specified by the address information.
The applicant of the present invention has also proposed a technology for automatically compositing and copying images such as maps printed across a plurality of pages in Japanese Unexamined Patent Publication JP-A 6-181518 (1994). This technology will be explained below as a fourth prior art technology. According to a picture processing apparatus of the disclosure, a predefined symbol is previously marked at a part of a plurality of originals to be read containing an overlapping image. Then, a plurality o
Akagi Hiroshi
Hirosawa Masashi
Kitamura Yoshihiro
Nakamura Mituaki
Nakamura Yasuhisa
Conlin David G.
Dike Bronstein, Roberts & Cushman LLP
Manus Peter J.
Mariam Daniel G.
Sharp Kabushiki Kaisha
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