Image reading apparatus

• US 5,128,777 A
• Filed: 11/17/1989
• Issued: 07/07/1992
• Est. Priority Date: 11/18/1988
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Uno, Teruhiko
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Grant, II, Jerome
• Application Number:
  US07/437,893
• Time in Patent Office: 963 Days
• Field of Search: 358/447, 358/448, 358/452, 358/453, 358/462, 358/464, 358/451, 358/467, 358/474, 358/486
• US Class Current: 358/448
• CPC Class Codes: H04N 1/0402 Scanning different formats; Scanning with different densities of dots per unit length, e.g. different numbers of dots per inch (dpi); Conversion of scanning standards H04N1/00283 takes precedence; picture signal circuits for modification of image resolution H04N1/3935, H04N1/40068
• CPC Class Codes: H04N 1/0411 in the main scanning direction
• CPC Class Codes: H04N 1/0417 Conversion of standards
• CPC Class Codes: H04N 1/0443 Varying the scanning velocity or position
• CPC Class Codes: H04N 1/1013 with sub-scanning by translatory movement of at least a part of the main-scanning components H04N1/107 takes precedence
• CPC Class Codes: H04N 1/40068 Modification of image resolution, i.e. determining the values of picture elements at new relative positions H04N1/3935 takes precedence

Abstract

An image reading apparatus for reading image formed on a document. The apparatus includes a scanner for scanning the image and forming image data, a driver for driving the scanner, a data processor for processing the image data and outputting information generated from the image data, a memory storing the output information from the data processor and a controller for setting a large thinning rate to be used by the data processor at a rough reading operation.

Claims

1. A method for reading images formed on a document, comprising the steps of:

performing a rough reading operation that tends to suppress details by scanning the images at a relatively high speed with an image scanning means;

generating image data from the image scanning means;

thinning the image data at a relatively high thinning rate to produce thinned image data;

using the thinned image data to designate a portion of the image to be read in a normal reading operation;

performing a normal reading operation on the designated portion of the image by scanning the selected portion at a relatively low speed with the image scanning means;

generating designated image data from the image scanning means; and

thinning the designated image data at a low thinning rate.

2. A method of reading an image on a document comprising the steps of:

pre-scanning the image at a rough scanning speed for producing rough image data;

storing the rough image data;

displaying a rough image corresponding to the stored rough image data;

designating a prescribed region on the rough image;

setting a prescribed distinct scanning speed; and

rescanning the image in the designated region at a prescribed distinct scanning speed lower than the rough scanning speed.