Soft-Test/Repair of CCD-Based Digital X-Ray Instrumentation


Modern x-ray imaging systems evolve toward digitization for reduced cost, faster time-to-diagnosis and improved diagnostic confidence. For the digital x-ray systems, CCD (Charge Coupled Device) technology is commonly used to detect and digitize optical x-ray image. This paper presents a novel soft-test/repair approach to overcome the defective pixel problem in CCD (Charge Coupled Device)-based digital x-ray system through theoretical modeling and analysis of the test/repair process. There are two possible solutions to cope with the defective pixel problem in CCD; one is the hard-repair approach and another is the proposed soft-test/repair approach. Hard-repair approach employs a high-yield, expensive reparable CCD to minimize the impact of hard-defects on the CCD, which occur in the form of noise propagated through AID converter to the frame memory, Therefore, less work is needed to filter and correct the image at the end-user level while it maybe exceedingly expensive to practice. On the other hand, the proposed soft-test/repair approach is to detect and tolerate defective pixels at the digitized image level; thereby it is inexpensive to practice and on-line repair can be done for non-interrupted service. It tests the images to detect the detective pixels and filter noise at the frame memory level, and caches them in a flash memory in the controller for future repair. The controller cache keeps accumulating all the noise coordinates, and preprocesses the incoming image data from the A/D converter by repairing them. The proposed soft-test/repair approach is particularly devised to facilitate hardware level implementation ultimately for real-time tele-diagnosis. Parametric simulation results demonstrate the speed and virtual yield enhancement by using the proposed approach; thereby highly reliable, yet inexpensive soft-test/repair of CCD-based digital x-ray systems can be ultimately realized.

Meeting Name

20th IEEE Instrumentation and Measurement Technology Conference: IMTC (2003: May 20-22, Vail, CO)


Electrical and Computer Engineering

Keywords and Phrases

Analog to Digital Conversion; Charge Coupled Devices; Digital Instruments; Repair; X Rays; Analog to Digital Conversion; Cache Memory; Flash Memory; Repair; Testing; X Ray Analysis; X Ray Apparatus; Digital X-Ray Instrumentation; Imaging Systems; Pixels; Diagnostic Confidence; Parametric Simulations; Teleradiology; Theoretical Modeling; Virtual Yield; X Ray Imaging System; X-Ray Instrumentation; Yield; CCD (Charge Coupled Device); Defective Pixels; Digital X-Ray; Tele-Diagnosis; Tele-Radiology; Testing

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International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version


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© 2003 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 May 2003