Method and apparatus for calibrating image system

• US 5,801,962 A
• Filed: 04/05/1996
• Issued: 09/01/1998
• Est. Priority Date: 04/05/1996
• Status: Expired due to Term

• Current Assignee: Transpacific Optics LLC (Intellectual Ventures LLC)
• Original Assignee: Must System, Inc.
• Inventors: Sheu, Rich, Wu, Jung-Fu, Wang, Ming-Song
• Primary Examiner(s): Voeltz, Emanuel Todd
• Assistant Examiner(s): COLE, TONY MITCHELL
• Application Number:
  US08/626,141
• Time in Patent Office: 879 Days
• Field of Search: 364/526, 364/571.01, 364/571.02, 348/615, 382/274, 395/126, 395/128, 395/131, 395/132, 358/406, 358/461, 358/463, 358/494, 358/504, 358/509, 358/518, 358/505, 358/520, 358/475, 358/474
• US Class Current: 702/85
• CPC Class Codes: H04N 1/40006 Compensating for the effects of ageing, i.e. changes over time
• CPC Class Codes: H04N 1/4072 dependent on the contents of the original

Abstract

A method and apparatus for calibrating an image system is disclosed. The method according to the present invention includes inputting data by scanning a plurality of lines into a computer, and analyzing the input data for generating intensity of the scanned lines. The inputting step is repeated when the intensity is less than a low threshold value or the intensity is higher than a high threshold value. Next, any scanned line that includes at least a special point is filtered out. After averaging the corresponding points of the scanned lines not filtered out in order to generate a calibration line, a predetermined number of points of the calibration line are averaged to generate a reference point, wherein the predetermined number of points of the calibration line are brighter than other points of the calibrated line. Finally, the calibration data are obtained by taking ratio of the reference point to each of the points of the calibration line.

Claims

1. A method for generating calibration data in an image system, comprising:

inputting data by scanning a plurality of lines into a computer;

analyzing said input data for generating intensity of the scanned lines;

repeating the inputting step when the intensity is less than a low threshold value or the intensity is higher than a high threshold value;

filtering out any scanned line that includes at least a special point;

averaging the corresponding points of the scanned lines not filtered out to generate a calibration line;

averaging a predetermined number of points of the calibration line to generate a reference point, said predetermined number of points of the calibration line are brighter than other points of the calibrated line; and

obtaining the calibration data by taking ratio of the reference point to each of the points of the calibration line.

2. The method according to claim 1, further comprising storing the calibration data on the computer.

3. The method according to claim 1, wherein said corresponding points of the scanned lines not filtered out are taken every several points.

4. A calibration method, comprising:

inputting data by scanning a plurality of lines into a computer;

analyzing said input data for generating intensity of the scanned lines;

repeating the inputting step when the intensity is less than a low threshold value or the intensity is higher than a high threshold value;

filtering out any scanned line that includes at least a special point;

averaging the corresponding points of the scanned lines not filtered out to generate a calibration line;

averaging a predetermined number of points of the calibration line to generate a reference point, said predetermined number of points of the calibration line are brighter than other points of the calibrated line;

obtaining the calibration data by taking ratio of the reference point to each of the points of the calibration line;

multiplying scanned image data by the corresponding calibration data to generate calibrated image;

replacing the scanned image data with a brightest image value when overflow occurs after the multiplying step; and

displaying the calibrated image.