Patents by Inventor Tuan H. Phan

Tuan H. Phan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Modulation transfer function test compensation for test pattern duty cycle
    Patent number: 5959726
    Abstract: Improving accuracy of frequency response measurements of linear systems using modulation transfer function test compensation. An optical imaging system illuminates and images an input test pattern. A processor measures a modulation transfer function. The processor determines a compensating factor for error in the input test pattern duty cycle. The driving function for the measurement is a test pattern having a periodic waveform approximating a square wave with an error in duty cycle. A windowed fast fourier transform on a greyscale image of the test pattern generates odd harmonics. Adjusting amplitude values of the odd harmonics corrects for the error in resolution target duty cycle.
    Type: Grant
    Filed: July 25, 1997
    Date of Patent: September 28, 1999
    Assignee: NeoPath, Inc.
    Inventors: James K. Riley, William E. Ortyn, Yuhui Cheng, Tuan H. Phan, Wayne A. Biggs