公开(公告)号：US5987221A

公开(公告)日：1999-11-16

申请号：US788768

申请日：1997-01-24

申请人： James G Bearss ,  Eugene A Roylance ,  Terry M. Nelson ,  Arlin R Jones

发明人： James G Bearss ,  Eugene A Roylance ,  Terry M. Nelson ,  Arlin R Jones

IPC分类号： B41J2/52 ,  B41J21/00 ,  G06F3/12 ,  G06T5/00 ,  H04N1/40 ,  H04N1/405 ,  H04N1/409 ,  G06K9/34 ,  G06K9/44 ,  G06K15/02

CPC分类号： H04N1/40062

摘要： Text and line art image data is distinguished from halftone image data for selectively enhanced rendering thereof. Specifically, a method of rendering a raster pixel image from a stored bitmap includes (i) determining whether an orphan pixel is detected within a bounded sampling window of the bitmap, and, (ii) processing at least one selected pixel of the bitmap within the sampling window relative to the determining of whether an orphan pixel is detected. In general, an orphan pixel is defined as an isolated white or black pixel in a halftone image. In one embodiment, an orphan pixel is recognized as having a predefined pixel value and as having no other pixels with that value adjacent thereto within the sampling window. In the event an orphan pixel is detected within the window, then the bitmap within the window is determined to be halftone image data and the selected pixel is processed accordingly. In the event an orphan pixel does not exist within the window, then the bitmap within the window is recognized as text or line art image data and processed respectively. In addition, a method of forming a dither matrix for a halftone image includes generating a pixel pattern such that an orphan pixel exists within the pattern of the dither matrix. The orphan pixel is designed into the halftone image. This measure increases the probability that orphan pixels will exist and be detected in the resultant raster image array. Thus, during subsequent rendering of the raster pixel image, selective application of resolution enhancement techniques may occur based on whether or not an orphan pixel is detected in the sampling window.

摘要翻译： 文本和线条艺术图像数据与半色调图像数据区分开，以便选择性地增强其再现。 具体来说，从存储的位图中渲染光栅像素图像的方法包括（i）确定在位图的有界采样窗口内是否检测到孤立像素，以及（ii）处理位图内的位图的至少一个选定像素 相对于确定是否检测到孤立像素的采样窗口。 通常，孤立像素被定义为半色调图像中的孤立的白色或黑色像素。 在一个实施例中，孤立像素被识别为具有预定义的像素值，并且在采样窗口内不具有与其相邻的值的其它像素。 在窗口内检测到孤立像素的情况下，窗口内的位图被确定为半色调图像数据，并且相应地处理所选择的像素。 在窗口内不存在孤立像素的情况下，窗口内的位图被识别为文本或线条图像数据并被分别处理。 此外，形成半色调图像的抖动矩阵的方法包括生成像素图案，使得孤立像素存在于抖动矩阵的图案内。 孤立像素被设计成半色调图像。 这种措施增加了孤立像素将存在并在最终的光栅图像阵列中被检测的可能性。 因此，在随后渲染光栅像素图像期间，基于在采样窗口中是否检测到孤立像素可以选择性地应用分辨率增强技术。