公开(公告)号：US5315409A

公开(公告)日：1994-05-24

申请号：US838496

申请日：1992-02-19

申请人： Akira Matsumura ,  Ryuji Kitakado

发明人： Akira Matsumura ,  Ryuji Kitakado

IPC分类号： H04N1/403 ,  G06K9/38 ,  G06T1/00 ,  G06T5/00 ,  G06T5/40 ,  H01N1/40

CPC分类号： G06K9/38 ,  G06T5/009 ,  G06T2207/20148 ,  G06T2207/30141

摘要： A frequency distribution or histogram M (L.sub.j-1, L.sub.j) of differences between gradation levels (L.sub.j-1, L.sub.j) of adjacent pixels (P.sub.j-1, P.sub.j) in an image is obtained, and the number of level-changes for each tentative threshold level L.sub.j is determined as a function of the histogram of the level differencies. By using the number of level-changes, an optimum binarization threshold level is set by means of an adaptive thresholding method. Since the number of level-changes is calculated from the histogram of the level-differencies without practical binarization for each threshold level, the amount of calculations is not dependent on the number of pixels but on the number of gradation levels. The calculations for setting the threshold level for the binarization of the image are achieved at high speeds by a small-scale hardware.

摘要翻译： 获得图像中的相邻像素（Pj-1，Pj）的灰度等级（Lj-1，Lj）之间的差的频率分布或直方图M（Lj-1，Lj），并且获得每个 确定临时阈值水平Lj作为水平差异的直方图的函数。 通过使用电平变化的数量，通过自适应阈值法来设置最优二值化阈值电平。 由于根据电平差异的直方图计算出电平变化的数量，而对于每个阈值电平没有实际的二值化，所以计算量不依赖于像素的数量，而是依赖于灰度级数。 用于设置图像二值化阈值水平的计算是通过小规模硬件在高速度下实现的。

公开(公告)号：US5144132A

公开(公告)日：1992-09-01

申请号：US734926

申请日：1991-07-24

申请人： Ryuji Kitakado

发明人： Ryuji Kitakado

IPC分类号： G01B11/00 ,  G01N21/88 ,  G01N21/93 ,  G01N21/956 ,  G06T1/00 ,  H04N1/047 ,  H05K3/00

CPC分类号： G01N21/956 ,  H04N1/047 ,  H04N2201/04729 ,  H04N2201/04789

摘要： A device for inspecting a printed board has linear image sensors. The image sensors read the image of the printed board on respective image reading positions (CA0, CB0, CA1, CB1), while scanning the image. A predetermined tolerance range (RY) for image-reading positions is previously determined so that the respective image reading positions are included in the tolerance range. Image signals obtained in respective image sensors are delayed by respective delay times. The respective delay times are previously determined in proportion to the deviations between the image reading positions and a reference position (RLY1), where the reference position is defined on the rear end (EPY1) or behind the tolerance range in the scanning direction (-Y). Through the delay process, all of the image signals are corrected to compensate for the respective deviations in the image reading positions.