The derivative-free Fourier shell identity for photoacoustics

The derivative-free Fourier shell identity for photoacoustics

In X-ray tomography, the Fourier slice theorem provides a relationship between the Fourier components of the object being imaged and the measured projection data. The Fourier slice theorem is the basis for X-ray Fourier-based tomographic inversion techniques. A similar relationship, referred to as the 'Fourier shell identity' has been previously derived for photoacoustic applications. However, ...

Derivative Free Optimization

Derivative-Free Optimization

In many engineering applications it is common to find optimization problems where the cost function and/or constraints require complex simulations. Though it is often, but not always, theoretically possible in these cases to extract derivative information efficiently, the associated implementation procedures are typically non-trivial and time-consuming (e.g., adjoint-based methodologies). Deriv...

Derivative free optimization method

Derivative free optimization (DFO) methods are typically designed to solve optimization problems whose objective function is computed by a “black box”; hence, the gradient computation is unavailable. Each call to the “black box” is often expensive, so estimating derivatives by finite differences may be prohibitively costly. Finally, the objective function value may be computed with some noise, ...

Biomedical photoacoustics in China☆

During the last decade, along with its explosive growth globally, biomedical photoacoustics has become a rapidly growing research field in China as well. In particular, photoacoustic tomography (PAT), capable of imaging intact biological tissue in vivo at great depths, has generated intense interest among Chinese researchers. This review briefly summarizes the current status and recent progress...