Ptychographic intensity interferometry imaging under low dynamic ranges

Abstract

Typically, high gray-scale imaging requires a high dynamic range camera. High dynamic range is even more crucial to conventional lensless imaging methods such as coherent diffraction imaging, since the dynamic range highly determines the resolution of recovered images. We here propose that ptychographic intensity interferometry imaging (PIII) can detect a complicated-structure object under 1-bit dynamic range (each pixel outputs zero or one only), and reconstruct a high resolution gray-scale image. PIII ptychographically illuminates an object with random speckle light, generating a speckle-like intensity pattern on a detection plane. The second-order correlation of the speckle pattens reveals the power spectrum of the object. Although the depth information of the speckle patterns will be lost because of low dynamic range detections, a small number of multiple detections with different illuminating fields can effectively recover a high dynamic range power spectrum, resulting in a high resolution gray-scale image. A theoretical analysis and comprehensive simulations for the “cameraman” photo are given in this work, which shows that the image under 1-bit dynamic range deteriorates no more than 0.4 dB (peak-signal-to-noise ratio) in comparison to the 16-bit dynamic range one. This method reduces the cost and complexity of implementing a lensless imaging.