×

Image processing device

  • US 5,748,794 A
  • Filed: 05/24/1995
  • Issued: 05/05/1998
  • Est. Priority Date: 11/24/1992
  • Status: Expired due to Term
First Claim
Patent Images

1. An image processing apparatus comprising:

  • fixed mode setting means for setting fixed thresholds of low gradational level for digital image data of high gradation representing an image and for setting fixed quantizing values on the basis of the fixed thresholds;

    variable mode setting means for setting variable thresholds of low gradational level for the digital image data representing the image in accordance with image quality and for setting variable quantizing values on the basis of the variable thresholds;

    mode selection means for selecting either a fixed mode or a variable mode for processing the digital image data representing the image;

    gray level processing means for (a) quantizing all the digital image data representing the image using the fixed thresholds and the fixed quantizing values when the fixed mode is selected by said mode selection means and quantizing all the digital image data representing the image using the variable thresholds and the variable quantizing values when the variable mode is selected by said mode selection means, to provide quantized digital image data, (b) determining an error value between the digital image data representing the image and the quantized digital image data, and (c) distributing the error value of each attentional pixel of the quantized digital image data representing the image between pixels adjacent thereto; and

    scanning means for scanning the image to provide the digital image data representing the image, the digital image data being provided by said scanning means with sampled white image data scanned from a reference white document,said variable mode setting means determining a difference in a white level of the sampled white image data and a predetermined reference white level and setting the variable thresholds in accordance with the determined difference.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×