1. Field of the Invention
The present invention relates to an image processing apparatus for processing image information obtained by reading an image with an image sensor such as CCD.
2. Related Background Art
In a conventional image processing apparatus for processing the image information obtained by reading the image of an original document with an image sensor, as disclosed in the U.S. Pat. No. 4,439,790, among the image signals read by the image sensor, only those relating to the image are considered effective and entered for processing.
In such image processing apparatus, after reading the original document with the image sensor, the image information of only the image therein is released from said apparatus. Consequently, if the size of the image released to a display unit or a printer is smaller than the display frame of the display unit or the recording sheet, the image, for example characters, appears as if it is suspended in the air as shown in FIG. 1. Such image is not easy to look at, and the boundary between the original document and the background is often unrecognizable.
Particularly in an electronic image file in which plural image information are stored in a memory medium such as a magnetooptical disk and are retrieved afterwards, the size of the original document or the image arrangement thereon cannot be identified from the retrieved image.
There has therefore been desired an image processing apparatus capable of solving such drawbacks and clarifying the boundary between the image of the original document and the background, thereby improving the legibility of the image. Also desired is such apparatus capable of clarifying the boundary between the image of the original document and the background, even on a printer or a display unit.