Nowadays, the application of active detection technology becomes more and more widespread. It is required to separate the transmitter and receiver. To achieve such separation, synchronization between the transmitted and received signals is necessary. A common matching method is to send a synchronization signal, which requires additional channels. Or it can be implemented through protocols, such as using starting bits, which fails when part of the signal is lost or submerged by noise. In this paper we propose a new matching protocol using aperiodic coding and modified edit distance, which requires less data storage and may be easily integrated into the detector. The method is verified within a ghost imaging system, with separated transmitter and receiver. Even if the echo intensity is as low as the level of few photons, it still works well.
Ghost imaging via sparsity constraints (GISC) is an advanced imaging technique. The reconstruction quality of GISC is affected by the sparse ratio of the object, the regularization parameter, and the iteration number. Influences of these parameters on the peak signal-to-noise ratio (PSNR) of the reconstructed image are discussed and evaluated. The optimal regularization parameter and iteration number at different sparse ratios are given. Then the reconstructed images of GISC using the optimal parameters at different sparse ratios are shown. The improvement of the reconstruction quality of GISC utilizing the optimal parameters is confirmed through comparison with normalized ghost imaging. Finally, the reconstruction quality of GISC with random noise is analyzed, and a method to obtain the sparse ratio of the object by analyzing the signal of the bucket detector is discussed.
Correlation imaging experiments correlate the outputs from two photodetectors. The image can be obtained by calculating the correlation function between results of two detectors. To reconstruct image of the object, many frames of different speckles are required. Therefore, the speed of correlation imaging is strongly limited by the speed of modulation of the light field. Usually, we use Spatial Light Modulator (SLM) to load different random phase at different positions of a plane-wave light field. The refresh rate of the speckle fields is thus limited by the surface refresh rate of SLM. However, the response speed of each pixel when we control it independently is far greater than the refresh rate of the whole surface. Based on this fact, we propose to modulate each pixel independently with different sinusoidal signals, in order to improve the refresh rate of speckle field. To generate randomly fluctuations, the frequencies of different modulation signals are selected to be coprime. At the same time, we can know in advance the intensity distribution of the speckle field in every frame, since we know the phase of each pixel when every pulse light modulated by the SLM.
Dispersion cancellation was proposed to enhance the robustness against dispersion broadening in optical measurement device. Nonlocal dispersion cancellation is suggested to be a pure quantum effect. We propose a novel classical analogy of nonlocal dispersion cancellation, which use frequency anti-correlation to reduce the dispersion broadening to a large extent. The optimized condition is given and analyzed by comparing with quantum light source.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.