Time Label Combination Method for PET Systems

The patent segments the time label extraction process into multiple independent components: leading edge time label, trailing edge time label, and zero-crossing time label. Each component processes different aspects of the pulse signal independently, and their results are combined through covariance matrix estimation and least square optimization to achieve high accuracy while eliminating time walk effects.

The patent merges multiple time label extraction methods (leading edge discrimination, trailing edge discrimination, and zero-crossing discrimination) into a unified combination method. By combining the advantages of each method and using covariance matrix-based optimization, the system achieves both high precision and reliability, eliminating the time walk problem that plagues individual methods.

The patent replaces the traditional high-speed analog-to-digital conversion approach with a digital signal processing approach. Instead of relying on high sampling rates from hardware converters, the system uses digital algorithms (leading edge detection, trailing edge detection, zero-crossing detection) to extract time labels from digitally acquired pulse signals, significantly reducing hardware complexity and cost while maintaining or improving time resolution.

The patent changes the approach from hardware-based high sampling rate conversion to software-based digital signal processing. By transforming the problem domain from analog hardware performance to digital algorithm processing, the system achieves high time resolution without requiring expensive high-rate ADCs, effectively changing the critical parameter from sampling rate to processing algorithm.