Carlos Colodro-Conde

Evaluation of stereo correspondence algorithms and their implementation on FPGA

The accuracy of stereo vision has been considerably improved in the last decade, but real-time stereo matching is still a challenge for embedded systems where the limited resources do not permit fast operation of sophisticated approaches. This work presents an evaluation of area-based algorithms used for calculating distance in stereoscopic vision systems, their hardware architectures for implementation on FPGA and the cost of their accuracies in terms of FPGA hardware resources. The results show the trade-off between the quality of such maps and the hardware resources which each solution demands, so they serve as a guide for implementing stereo correspondence algorithms in real-time processing systems.

Laboratory and telescope demonstration of the TP3-WFS for the adaptive optics segment of AOLI

This work was supported by the Spanish Ministry of Economy under the projects AYA2011-29024, ESP2014-56869-C2-2-P, ESP2015-69020-C2-2-R and DPI2015-66458-C2-2-R, by project 15345/PI/10 from the Fundacion Seneca, by the Spanish Ministry of Education under the grant FPU12/05573, by project ST/K002368/1 from the Science and Technology Facilities Council and by ERDF funds from the European Commission. The results presented in this paper are based on observations made with the William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. Special thanks go to Lara Monteagudo and Marcos Pellejero for their timely contributions.

The on-board electronics for the near infrared spectrograph and photometer (NISP) of the EUCLID Mission

The Near Infrared Spectrograph and Photometer (NISP) is one of the instruments on board the EUCLID mission. The focal plane array (FPA) consists of 16 HAWAII-2RG HgCdTe detectors from Teledyne Imaging Scientific (TIS), for NIR imaging in three bands (Y, J, H) and slitless spectroscopy in the range 0.9−2µm. Low total noise measurements (i.e. total noise < 8 electrons) are achieved by operating the detectors in multiple non-destructive readout mode for the implementation of both the Fowler and Up-The-Ramp (UTR) sampling, which also enables the detection and removal of cosmic ray events. The large area of the NISP FPA and the limited satellite telemetry available impose to perform the required data processing on board, during the observations. This requires a well optimized on-board data processing pipeline, and high-performance control electronics, suited to cope with the time constraints of the NISP acquisition sequences. This paper describes the architecture of the NISP on-board electronics, which take charge of several tasks, including the driving of each individual HAWAII-2RG detectors through their SIDECAR ASICs, the data processing, inclusive of compression and storage, and the instrument control tasks. We describe the implementation of the processing power needed for the demanding on-board data reduction. We also describe the basic operational modes that will be managed by the system during the mission, along with data flow and the Telemetry/TeleCommands flow. This paper reports the NISP on-board electronics architecture status at the end of the Phase B1, and it is presented on behalf of the Euclid Consortium.

An instrumental puzzle: the modular integration of AOLI

The Adaptive Optics Lucky Imager, AOLI, is an instrument developed to deliver the highest spatial resolution ever obtained in the visible, 20 mas, from ground-based telescopes. In AOLI a new philosophy of instrumental prototyping has been applied, based on the modularization of the subsystems. This modular concept offers maximum flexibility regarding the instrument, telescope or the addition of future developments.

ALIOLI: Adaptive and Lucky Imaging Optics Lightweight Instrument

As a consequence of the evolution in the design and of the modularity of its components, AOLI for the William Herschel Telescope (WHT 4.2m) is much smaller and more efficient than its previous designs. This success has leaded us to plan to condense it even more to get a portable and easy to integrate system, ALIOLI (Adaptive and Lucky Imaging Optics Lightweight Instrument). It consists of a DM+WFS module with a lucky imaging science camera attached. ALIOLI is an AO instrument for the 1-2m class telescopes which will also be used as on-sky testbench for AO developments. Here we describe the setup to be installed at the 1.5m Telescopio Carlos Snchez (TCS) at the Spanish Observatorio del Teide (Tenerife, Canary Islands).

AOLI: near-diffraction limited imaging in the visible on large ground-based telescopes

The combination of Lucky Imaging with a low order adaptive optics system was demonstrated very successfully on the Palomar 5m telescope nearly 10 years ago. It is still the only system to give such high-resolution images in the visible or near infrared on ground-based telescope of faint astronomical targets. The development of AOLI for deployment initially on the WHT 4.2 m telescope in La Palma, Canary Islands, will be described in this paper. In particular, we will look at the design and status of our low order curvature wavefront sensor which has been somewhat simplified to make it more efficient, ensuring coverage over much of the sky with natural guide stars as reference object. AOLI uses optically butted electron multiplying CCDs to give an imaging array of 2000 x 2000 pixels.

Design and analysis of efficient synthesis algorithms for EDAC functions in FPGAs

Error detection and correction (EDAC) functions have been widely used for protecting memories from single event upsets (SEU), which occur in environments with high levels of radiation or in deep submicron manufacturing technologies. This paper presents three novel synthesis algorithms that obtain area-efficient implementations for a given EDAC function, with the ultimate aim of reducing the number of sensitive configuration bits in SRAM-based field-programmable gate arrays (FPGAs). Having less sensitive bits results in a lower chance of suffering an SEU in the EDAC circuitry, thus improving the overall reliability of the whole system. Besides minimizing area, the proposed algorithms also focus on improving other figures of merit like circuit speed and power consumption. The executed benchmarks show that, when compared with other modern synthesis tools, the proposed algorithms can reduce the number of utilized look-up tables (LUTs) up to a 34.48%. Such large reductions in area usage ultimately result in reliability improvements over 10% for the implemented EDAC cores, measured as MTBF (mean time between failures). On the other hand, maximum path delays and power consumptions can be reduced up to a 17.72% and 34.37%, respectively, on the placed and routed designs.

The adaptive optics lucky imager (AOLI): presentation, commissioning, and AIV innovations

Here we present the Adaptive Optics Lucky Imager (AOLI), a state-of-the-art instrument which makes use of two well proved techniques, Lucky Imaging (LI) and Adaptive Optics (AO), to deliver diffraction limited imaging at visible wavelengths, 20 mas, from ground-based telescopes. Thanks to its revolutionary TP3-WFS, AOLI shall have the capability of using faint reference stars. In the extremely-big telescopes era, the combination of techniques and the development of new WFS systems seems the clue key for success. We give details of the integration and verification phases explaining the defiance that we have faced and the innovative and versatile solutions for each of its subsystems that we have developed, providing also very fresh results after its first fully-working observing run at the William Herschel Telescope (WHT).

Real time phase compensation using a tomographical pupil image wavefront sensor (TPI-WFS)

This paper presents a method to recover the wavefront phase at the telescope pupil, distorted because of the atmosphere action, and its use to command a deformable mirror to compensate for the optical aberrations in real time (AOLI instrument). For this purpose, an evolution of the geometric sensor [1] was used to restore the wavefront from two defocused images. Furthermore, by using specialized hardware the computations can be performed in real time, within the stability time of the atmosphere.

The boot software of the control unit of the near infrared spectrograph of the Euclid space mission: technical specification

The Near Infrared Spectrograph and Photometer (NISP) is one of the instruments on board the ESA EUCLID mission. The Boot Software (BSW) is in charge of initialization and communications after a reset occurs at hard- ware level. The Universidad Politecnica de Cartagena and Instituto de Astrofisica de Canarias are responsible of the Instrument Control Unit of the NISP (NI-ICU) in the Euclid Consortium. The NI-ICU BSW is developed by Universidad de Alcal´a, and its main functions are: communication with the S/C for memory management, self-tests and start of a patchable Application Software (ASW). This paper presents the NI-ICU BSW status of definition and design at the end of the Technical Specification phase.