Partial Readout Research Articles

Determination of spectral resolutions for multispectral detection of apple bruises using visible/near-infrared hyperspectral reflectance imaging

This study demonstrates a method to select wavelength-specific spectral resolutions to optimize a line-scan hyperspectral imaging method for its intended use, which in this case was visible/near-infrared imaging-based multiple-waveband detection of apple bruises. Many earlier studies have explored important aspects of developing apple bruise detection systems, such as key wavelengths and image processing algorithms. Despite the endeavors of many, development of a real-time bruise detection system is not yet a simple task. To overcome these problems, this study investigated selection of optimal wavelength-specific spectral resolutions for detecting bruises on apples by using hyperspectral line-scan imaging with the Random Track function for non-contiguous partial readout, with two experimental parts. The first part identified key-wavelengths and the optimal number of key-wavelengths to use for detecting low-, medium-, and high-impact bruises on apples. These parameters were determined by principal component analysis (PCA) and sequential forward selection (SFS) with four classification methods. The second part determined the optimal spectral resolution for each of the key-wavelengths by selecting and evaluating 21 combinations of exposure time and key-wavelength bandwidths, and then selecting the best combination based on the bruise detection accuracies achieved by each classification method. Each of the four classification methods was found to have a different optimized resolution for high accuracy bruise detection, and the optimized resolutions also allowed for use of shorter exposure times. The results of this work can be used to help develop multispectral imaging systems that provide rapid, cost-effective post-harvest processing to identify bruised apples on commercial processing lines.

Data acquisition and trigger system for imaging atmospheric Cherenkov telescopes of the LHAASO

The Wide Field of View Cherenkov Telescope Array is an important part of the Large High Altitude Air Shower Observatory. The array adopts atmospheric Cherenkov imaging technology. The data acquisition and trigger system is central to each telescope's electronics readout system. To acquire as many Cherenkov events as possible, the system uses a two-level trigger design and partial readout technology. A telescope uses silicon photomultiplier tubes as the detector, whose status (e.g., in terms of the temperature and voltage) is monitored by the system. The instruction protocol of the system is presented.

Near-optimal decoding of transient stimuli from coupled neuronal subpopulations.

Coupling between sensory neurons impacts their tuning properties and correlations in their responses. How such coupling affects sensory representations and ultimately behavior remains unclear. We investigated the role of neuronal coupling during visual processing using a realistic biophysical model of the vertical system (VS) cell network in the blow fly. These neurons are thought to encode the horizontal rotation axis during rapid free-flight maneuvers. Experimental findings suggest that neurons of the VS are strongly electrically coupled, and that several downstream neurons driving motor responses to ego-rotation receive inputs primarily from a small subset of VS cells. These downstream neurons must decode information about the axis of rotation from a partial readout of the VS population response. To investigate the role of coupling, we simulated the VS response to a variety of rotating visual scenes and computed optimal Bayesian estimates from the relevant subset of VS cells. Our analysis shows that coupling leads to near-optimal estimates from a subpopulation readout. In contrast, coupling between VS cells has no impact on the quality of encoding in the response of the full population. We conclude that coupling at one level of the fly visual system allows for near-optimal decoding from partial information at the subsequent, premotor level. Thus, electrical coupling may provide a general mechanism to achieve near-optimal information transfer from neuronal subpopulations across organisms and modalities.

Study on the photo-transfer thermoluminescence in Eu doped potassium chloride

ABSTRACTIn this work a survey of possible optical stimulation processes in irradiated KCl:Eu with a focusing on photo-transfer thermoluminescence (PTTL) effects are shown. For different wavelengths in the range from 180 to 800 nm a cycle of measurements was performed, each comprising of a TL measurement after light irradiation, a TL measurement after beta irradiation for reference purposes and a PTTL measurement. The latter was obtained by applying first a beta irradiation, then a partial readout up to a certain end temperature followed by a monochromatic light irradiation of a specific wavelength and finally a TL measurement. This procedure was repeated for different partial readout end temperatures. From the results the existence of at least four different photo-transfer processes, induced by 310, 245 and 550 nm light are deduced. The photo transfer process induced by an approximate value of 245 nm produced a TL glow peak not seen before in beta or light induced TL. Furthermore it was observed that some of the TL peaks created by light of 240 and 260 nm were strongly sensitized after a beta irradiation and a partial readout.

A new family of pixel detectors for high frame rate X-ray applications

We are developing a new family of hybrid, single photon counting X-ray detectors for very high frame rate applications. A dedicated readout chip was designed, to be used as building block for detectors up to 9 Mpixel and about 550 cm 2 area. It has an area of 19.3 × 20.0 mm 2 and contains 256 × 256 pixels of 75 × 75 μ m 2 , resulting in an active region of 19.2 × 19.2 mm 2 . Each pixel contains a 12 bit counter with double buffering for continuous image acquisition. Moreover, it allows a partial readout (4, 8 or 12 bits) with corresponding frame rates up to 24, 12 and 8 kHz. The chip is designed with Hardening By Design techniques [1], to obtain high radiation tolerance from a standard commercial 0.25 μ m CMOS technology. The chip was recently received from fabrication and it is at present under test.

Robust and efficient quantum repeaters with atomic ensembles and linear optics

In the last few years there has been a lot of interest in quantum repeater protocols using only atomic ensembles and linear optics. Here we show that the local generation of high-fidelity entangled pairs of atomic excitations, in combination with the use of two-photon detections for long-distance entanglement generation, permits the implementation of a very attractive quantum repeater protocol. Such a repeater is robust with respect to phase fluctuations in the transmission channels, and at the same time achieves higher entanglement generation rates than other protocols using the same ingredients. We propose an efficient method of generating high-fidelity entangled pairs locally, based on the partial readout of the ensemble-based memories. We also discuss the experimental implementation of the proposed protocol.