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Machine learning algorithms are powerful tools in Bayesian uncertainty quantification (UQ) of inverse problems. Unfortunately, when using these algorithms medical imaging practitioners are faced with the challenging task of manually defining neural networks that can handle complicated inputs such as acoustic data. This task needs to be replicated for different receiver types or configurations since these change the dimensionality of the input. We propose to first transform the data using the adjoint operator —ex: time reversal in photoacoustic imaging (PAI) or back-projection in computer tomography (CT) imaging — then continue posterior inference using the adjoint data as an input now that it has been standardized to the size of the unknown model. This adjoint preprocessing technique has been used in previous works but with minimal discussion on if it is biased. In this work, we prove that conditioning on adjoint data is unbiased for a certain class of inverse problems. We then demonstrate with two medical imaging examples (PAI and CT) that adjoints enable two things: Firstly, adjoints partially undo the physics of the forward operator resulting in faster convergence of a learned Bayesian UQ technique. Secondly, the algorithm is now robust to changes in the observed data caused by different transducer subsampling in PAI and number of angles in CT. Our adjoint-based Bayesian inference method results in point estimates that are faster to compute than traditional baselines and show higher SSIM metrics, while also providing validated UQ.

Gabor zone plate (GZP) is typical amplitude-type diffractive lenses for high-resolution imaging. Compared with Fresnel zone plates (FZP), GZP can suppress all higher-order foci and shows better focusing performance. However, the focusing efficiency of GZP is very low and the cosine variation of its transmittance is difficult to satisfy. In order to improve these disadvantages, many kinds of improved Gabor zone plates are designed. However, the focusing efficiency of these Gabor zone plates are ~10%, which is still too low. A phase-type diffractive lens based on the Gabor zone plate is designed to improve the focusing efficiency of GZP, in which the radial distribution of microstructure varies in a cosine pattern. Simulation results show that the focusing efficiency of the Gabor-type diffractive lens (GDL) can reach ~22%, which is much higher than that of GZP. In addition, we also analyze the effect of errors of laser direct writing on the focusing efficiency of GDL and Fresnel-type diffractive lens (FDL). The results show that the focusing efficiency of GDL shows higher tolerance for the error of laser direct writing than that of FDL.

Basic principle, modeling method, error analysis and process design of products assembly and adjustment are analyzed. In order to improve the resolution of the imaging system and reach the theoretical limit, the off-axis system optimization method is promoted from the perspective of theory to engineering. The simulation results show that the system can meet the application requirements of MTF and other related criteria. And an engineering method is explored for real-time construction and control of dynamic systems.

The principle approach, modeling, and error analysis are analyzed, and the system configuration based on freeform is advanced proposed in the algorithm analysis. In order to improve the resolution of the imaging system and reach the theoretical limit, the off-axis system optimization method is promoted from the perspective of theory to engineering. The simulation results show that the system can meet the application requirements of MTF, REA, RMS and other related criteria. Moreover, the system has reduced in volume and weight significantly.

The laser rangefinder and the mapping camera have strong complementarity in the positioning of the ground target, and the combination of the two can obtain a better three-dimensional positioning accuracy of the ground target.In order to achieve highly accurate positioning of ground targets, meet the needs of large-scale surveying and mapping, and provide the required elevation control points for the stereo surveying and mapping camera, it is necessary to accurately measure the position of the laser footprint.A method for determining the position of the laser footprint based on a footprint camera is proposed. First, a low-resolution footprint camera is used to directly record the laser emission direction, and then the low-resolution footprint camera is recorded by a method based on image feature point matching. The position of the laser footprint is matched to the image of the high-resolution stereo surveying and mapping camera, and finally the direction of the emitted laser is accurately determined. This method is not related to the attitude determination error of the laser rangefinder and the internal orientation element determination of the footprint camera. Through error analysis, it can meet the 1:10 000 scale positioning accuracy requirement.

Target alignment technology is one of the most critical technologies in high-energy physics experiments, and is an important technology related to the success of the laser fusion experiment. This paper describes the error in the basic target alignment scheme, and designs a series of alignment fiducials around the target to achieve the improvement in target alignment precision. This paper analyzes the influence of fiducials-group’s forms on the target alignment error. According to their respective properties, under the constraints of the experimental conditions, and combined with the linear and nonlinear fiducials-group’s design, improvement of target alignment precision and error transfer are achieved. Under the experimental requirements of the SG-II-U facility, combined with the working conditions, a surrogate target with alignment fiducials-group is designed, and through the interaction of the fiducials-group and the alignment mark in viewers, the error of target recognition can be greatly optimized and the uncertainty of target alignment can be reduced.

Generating reference on the back focal plane (BFP) of objective lens has been an excellent solution for numerical aperture (NA) measurement. Although the effectiveness of the concept of BFP reference has been verified theoretically and experimentally, there has been no practical apertometer based on this concept. The main challenge is how to realize the assembly of the system. In this work, we present the instrument assembly of the apertometer based on BFP reference, which mainly has three requirements. After that, we specifically investigate the influence of the location of the coverslip on BFP image and NA value by using ZEMAX. This work promotes the instrumentation of BFP-typed apertometer significantly.

The theory of compound zoom system and its influence and control on aberration are the basis for the design of such systems and have practical value in engineering. The principle, modeling and error analysis are analyed. Based on the system configuration of the compound zoom system, moreover, this paper advances the algorithm analysis.

The theory of compound zoom system and its influence and control on aberration are the basis for the design of such systems and have practical value in engineering. The principle, modeling and error analysis are analyed. Based on the system configuration of the compound zoom system, moreover, this paper advances the algorithm analysis.

One of the main concerns in adopting citizen science is data quality. Derived products inherit intrinsic limitations of the capture methodology as well as the uncertainties in observations. OpenStreetMap tools are designed to minimize uncertainties in positional accuracy by ensuring a good co-registration of the observations with imagery or direct use of GPS. When thematically annotating objects contributed by citizens, uncertainty increases. During the H2020 GroundTruth 2.0 project two land-cover products derived from OSM were analyzed; one created by the University of Heidelberg (http://osmlanduse.org) and another elaborated by University of Coimbra (https://vgi.uc.pt/vgi/osm/osm2lulc/). To be able to assess the quality of both maps, a third product derived from remote sensing was introduced as a reference map. In GroundTruth 2.0 a tool to show and compare maps as part of the MiraMon Map Browser was developed. The objective was to allow final users to auto-evaluate the quality of their region of interest. The confusion matrix has been used as a method to derive overall commission and omission estimators as well as the Kappa coefficient. Most of the discrepancies between OSM and remote sensing (RS) derived maps are related to different approaches used during data capturing. The data quality tool assesses the quality of individual observations exposed using the OGC standard and describes the quality in an interoperable approach based on QualityML.

Purpose We present a systematic error analysis for a navigation system which allows image fusion between two arbitrary image modalities. A prototype was built for prostate biopsies merging pre-operative magnetic resonance images (MRI) with interventional 3D free-hand transrectal US (TRUS). Methods The fusion between MRI and TRUS images was performed by replacing the inter-modal MRI-TRUS registration by an intra-modal 3D/3D-US/TRUS registration and a pre-operative image fusion between MRI and 3D(-abdominal)-US using an optical tracking system (OTS). The error of the inter-modal MRI/3D(-abdominal)- US image fusion was evaluated using a multi-cone phantom and a prostate phantom by calculating a target registration error (TRE) and the Dice score of segmented lesions (radius 5 mm) from the prostate phantom. The pre-operative 3D(-abdominal)-US was then registered with the TRUS images and the TRE error was calculated. Finally, a Dice score of segmented lesions between TRUS and MRI was determined. Results The fiducial registration error for the 3D(-abdominal)-US and TRUS calibration resulted in 0:87 mm and 1:18 mm, respectively. The TRE for the 3D abdominal transducer was 1:08 mm. The TRE of the MRI/3D- US image fusion using a multi-cone phantom was 1:81 mm. The Dice-score calculated from test lesions segmented in MRI and TRUS resulted in an error of 0.67. The TRE between the 3D-US and the TRUS was 2:10 mm. The Dice score from segmented lesions in MRI and TRUS was 0:67. Conclusions The intra-modal registration via OTS between MRI and TRUS images showed sufficient accuracy for prostate biopsy.

The casing is one of the key components in the aeroengine. It is a typical complex thin-walled structure, and has the characteristics of large component size, many structural elements, complex profile, huge measurement workload, thin structure and easy deformation, and high precision. The requirements of measuring efficiency and measurement accuracy are getting higher and higher. At present, the three-coordinate measuring machine (CMM) is widely used to measure aeroengine casing in China's aeroengine manufacturers. Taking some casing as an example, CMM is required to measure 256 items, and the measuring period is more than 1 day. In order to reduce the workload and improve the efficient in measuring aeroengine casing, the research develops a multi-axis measuring system based on a high-precision turntable, which has been improved to meet the performance. At the same time, the error of the multi-axis measurement system is discussed to achieve high precision and high efficiency measurement.

SPIE Optics + Photonics; August 11, 2019 - August 15, 2019; San Diego, CA; United States, Coronagraph-equipped direct imaging missions need an active wavefront control system to cancel out the optical aberrations that degrade the performance of the coronagraphs. A fast steering mirror is used to control Line-of-Sight (LoS) pointing error caused by the telescope jitter. In addition to controlling other low-order aberrations such as astigmatism and coma, high stroke, high actuator density deformable mirrors (DMs) are also used to control the electric field at the required high spatial frequencies. We are designing a testbed to verify a different deformable architecture, where the powered optic in the optical train are controllable and have lower actuator count compared to the existing DMs with flat nominal surfaces. This simplifies the packaging issue for space missions and reduces both cost and risk of having the entire coronagraph instrument's performance depending on one or two high-actuator count DMs. The testbed would also be capable of testing different low-order wavefront sensing algorithms, which focuses in the near-term on a new adaptive Kalman filtering and gradient decent method to estimate the harmonic LoS errors that affect space telescopes. In long run, we would test different machine learning techniques to estimate low-order aberrations and non-linear algorithms for digging the region of high contrast called the dark holes (DH).

Laser is used for remote charging of UAV instead of sunlight to improve charging power, continuous charging performance and endurance of UAV. Laser alignment is one of the key technologies for laser charging. On the basis of briefly describing the composition and working process of the laser charging system, the method, module composition, working process and key process based on beacon laser alignment are emphatically analyzed. Combined with the whole working process of the laser charging system, the error factors affecting the charging accuracy are analyzed, and the reasonable error distribution is carried out to provide theoretical basis for the system realization.

The measurement of spindle radial error motion is achieved based on target trajectory tracking (TTT). Error analysis of TTT method is performed in this paper. Target trajectory doesn’t contain information about axial error motion. The tilt error motion is included in the target trajectory. However, the tilt error motion is small enough to be ignored. The roundness error of the target trajectory is assessed to obtain the radial error motion of the spindle. The experimental results confirm that the proposed method can be applied to measure the radial error motion of a high-speed spindle having a maximum rotational speed of 6000r/m.

A non-contact blood pressure measurement method was proposed and achieved based on theoretical deduction of the relationship among pulse transit time, heart rate and blood pressure. Pulse transit time was estimated using heart rate and phase difference of pulse wave which were obtained from color videos through imaging photoplethysmographic. Parameters of the functional relationship were determined through curve fitting with experiment data. Error analysis was processed with an Omron electronic sphygmomanometer as reference to verify the accuracy of blood pressure obtained using the proposed method. The error of acquired systolic blood pressure varied from -2.40 to 3.43 percent. The error of acquired diastolic blood pressure varied from -6.88 to 5.26 percent.

An experimental method is used to measure the optical parameters of a GRIN lens. The intrinsic properties of the lens are well characterized by measuring the intercept values of the different GRIN lenses. Firstly, the intercept equation is derived from the transmission matrix of the GRIN lens, and the measurement method is described in detail. Secondly, we design and make the optical path measuring system. Finally, the error analysis of the experimental results is presented, which shows the feasibility of the working principle and the experiment operation. The principle and equipment of this measuring method are relatively effective, which affords great practical significance for the measurement of the GRIN lens.

The multistep registration(MSR) method in [1] is to register two different classes of sensors deployed on z-arm of CMM(coordinate measuring machine): a video camera and a tactile probe sensor. In general, it is difficult to obtain a very precise registration result with a single common standard, instead, this method is achieved by measuring two different standards with a constant distance between them two which are fixed on a steel plate. Although many factors have been considered such as the measuring ability of sensors, the uncertainty of the machine and the number of data pairs, there is no exact analysis on the squareness between the x-axis and the y-axis on the xy plane. For this sake, error analysis on the squareness of multi-sensor integrated CMM for the multistep registration method will be made to examine the validation of the MSR method. Synthetic experiments on the squareness on the xy plane for the simplified MSR with an inclination rotation are simulated, which will lead to a regular result. Experiments have been carried out with the multi-standard device designed also in [1], meanwhile, inspections with the help of a laser interferometer on the xy plane have been carried out. The final results are conformed to the simulations, and the squareness errors of the MSR method are also similar to the results of interferometer. In other word, the MSR can also adopted/utilized to verify the squareness of a CMM.

The error structure of fiber based displacement interferometers was studied, and an error compensation system developed. Experimental verification was achieved, contrasting gravitational acceleration between theoretical and measured results. The effective measurement velocity range was large with excellent precision.

The accurate warning and reconnaissance to incoming laser signal is the presupposition of electro-optical jamming. However, the error of angular resolution of laser warning equipment directly affects the accuracy of warning. In this paper, the working mechanism of direct intercepting measurement laser warning equipment was analyzed. Then, the structure of its detector array system and the causes of error of angular resolution were analyzed. At different distance, the resolution errors of laser warning equipment with different detecting unit were calculated. The conclusion has some reference value to test and detect of such equipment.

Generally adaptive speed system is an important direction in the development of computational imaging. Computational theory of imaging system and its influence on aberration and control, is the basis to develop such a system design, which has application value aspects. The principle approach, modeling, and error analysis are analyzed, and the system configuration based on adaptive is advanced in algorithm analysis.

Generally adaptive speed system is an important direction in the development of computational imaging. Computational theory of imaging system and its influence on aberration and control, is the basis to develop such a system design, which has application value aspects. The principle approach, modeling, and error analysis are analyzed, and the system configuration based on adaptive is advanced in algorithm analysis.

Freeform system theory and its influence on aberration and control, is the basis to develop such a system design, which has application value in engineering aspects. The principle approach, modeling, and error analysis are analyzed, and the system configuration based on freeform is advanced in algorithm analysis.

Specular gloss has been widely used to characterize the ability of a surface to reflect light specularly. Specular gloss is theoretically related to the physical properties of a surface, such as roughness, directionality and uniformity. Specular gloss, mainly determined by incident angle and refractive index of a surface, is a relative measurement quantity. Specular gloss is usually measured by a glossmeter. The topographical and optical properties of a surface have been analyzed on how to affect the measurements. The experiment results indicate that a less rough/flatter, more isotropic and more uniform surface will result in a more accurate measurement value. Therefore, physical properties of a surface must be carefully inspected before the specular gloss measurement in order to acquire a satisfied result.

It is hard to get high-precision measurement of the radius of curvature (ROC), because of many factors that affect the measurement accuracy. For the measurement of long radius of curvature, some factors take more important position than others'. So, at first this paper makes some research about which factor is related to the long measurement distance, and also analyse the uncertain of the measurement accuracy. At second this article also study the influence about the support status and the adjust error about the cat’s eye and confocal position. At last, a 1055micrometer radius of curvature convex is measured in high-precision laboratory. Experimental results show that the proper steady support (three-point support) can guarantee the high-precision measurement of radius of curvature. Through calibrating the gain of cat's eye and confocal position, is useful to ensure the precise position in order to increase the measurement accuracy. After finish all the above process, the high-precision long ROC measurement is realized.

In recent years, MODIS data were widely used in dynamic monitoring of Green Tide. However, the images may contain lots of mixed pixels because of coarse resolution ,which will cause the error of the monitor result1,2. In this paper, the monitoring error was quantitatively analyzed with the help of GF-1 WFV data, which has a high resolution of 16 merers and the monitoring result of which were considered to be accurate. The conclusions are as follows: there are errors in both dense and sparse Enteromorpha monitoring using MODIS data, and the error in sparse Enteromorpha is larger. Most of the error is concentrated on the edge of the floating Enteromorpha patch. MODIS has a good ability in observing the location of Enteromorpha , and it can play an important role in the dynamic monitoring of multi source data.

The use of the polarimetry techniques for display and study of biological tissues has gained increasing interest in recent years. This interest is related mainly to the non-invasiveness, relatively low cost, and ease of application among other characteristics. However, for full use of these advantages, the calibration methods must ensure the minimization of the effects of uncertainties related to the optical element positioning and the noise in intensities measurements.

Formaldehyde (HCHO) is involved in a lot of chemical reactions in the atmosphere. Taking into account that HCHO basically undergo by photolysis and reaction with hydroxyl radical within a few hours, short-lived VOCs and direct HCHO emissions can cause local HCHO enhancement over certain areas, and, hence, exceeding background level of HCHO can be examined as a local pollution of the atmosphere by VOCs or existence of a local HCHO source. Several retrieval algorithms applicable for DOAS measurements in cloudless were previously developed. A new algorithm applicable for overcast and cloudless sky and its error analysis is briefly introduced by this paper. Analysis of our HCHO VCD retrieval for overcast shows that when one know the cloud base height, but doesn’t know cloud optical depth, the typical errors of HCHO total content retrieval are less than 10% for snow season, less than 5% for snow-free seasons, and reaches 40-45% for season with non-stable snow cover. In case one knows both the cloud base height and the cloud optical depth, the typical errors are about 5% for snow season, less than 2.5% for snow-free seasons, and are within about 10–30% for season with non-stable snow cover. Given above error estimations are valid if the HCHO layer is below the cloud base. The errors dramatically increase when HCHO layer penetrates into clouds in both cases. The first preliminary results of HCHO VCD retrieval for overcast are shown. The average difference of the HCHO VCDs for wind from Moscow megapolis and wind from few urbanized areas is about 0.8×10 16 mol×cm -2 and approximately corresponds to estimates of influence of Moscow megapolis observed in clear-sky conditions.

A convenient method to study the influence of error sources in Fizeau is to build a ray-tracing model to simulate the error sources. In this paper an interferometer model is presented; an extension program is called to simulate the interference; and a preliminary research of several error sources is conducted. These examples demonstrate error analysis based on interferometer models is feasible and provide some guidance for optimizing our interferometer design.

As a new type of light dispersion device, Acousto-Optic Tunable Filter (AOTF) based on the acousto-optic interaction principle which can achieve diffractive spectral, has rapidly developed and been widely used in the technical fields of spectral analysis and remote sensing detection since it launched. The precise measurement of AOTF’s optical performance parameter is the precondition to ensure spectral radiometric calibration and data inversion in the process of quantitation for spectrometer based on AOTF. In this paper, a kind of AOTF performance analysis system in 450~3200nm wide spectrum was introduced, including the fundamental principle of the basic system and the test method of the key optical parameters of AOTF. The error sources and the influence of the magnitude of the error in the whole test system were analyzed and verified emphatically. The numerical simulation of the noise in detecting circuit and the instability of light source was carried out, and based on the simulation result, the method for improving the measuring accuracy of the system were proposed such as improving light source parameters, correcting and changing test method by using dual light path detecting, etc. Experimental results indicate that: the relative error can be reduced by 20%, and the stability of the test signal is better than 98%. Finally, this error analysis model and the potential applicability in other optoelectronic measuring system were also discussed in the paper.

The advanced photonics laboratory is a biannual course offered to graduate students, after they have taken a few basic courses in optics and photonics. The course contents include experiments involving different areas in optics and photonics. Learning outcome includes theoretical formulation in optical phenomena and adoption of its instruments. Students are encouraged to explore experimental parameters, observe the effect on measured quantities, correlate them to theoretical predictions and finally explain any discrepancies. The methodology encourages students to question both theoretical models and experimental techniques.

The modern state-of-the-art in general purpose design technique is discussed. An importance of taking into account additional practical demands in the course of designing is demonstrated. Special purpose design techniques capable to take into account specific practical demands are considered. Possible types of the pre-production error analysis are discussed in connection with the types of monitoring techniques used for coating production.

Phase-shifting is a well-known technique for phase retrieval that requires a series of intensity measurements with certain phase-steps. Harmonics and linear phase-shift errors are the main source of errors in interferometry. In this work we present a systematic algebraic approach for the generation of phase-shifting algorithms(for interferograms with arbitrarily phase-steps) insensitive to harmonics and linear phase-shift errors.

Phase errors are one of the sources of insufficient measurement accuracy of optical 3D surface sensors based on the fringe projection technique. In this paper phase error analysis and compensation is presented which successfully improves the measurement results of disturbed input data. The origins of the phase errors are analyzed and systematic and random errors are distinguished. An error model is introduced which allows the description of arbitrary and locally distinguishing phase errors. The presented new method includes phase error determination and correction independently from the origin of the phase error. Different compensation algorithms are presented which were successfully applied to selected examples of real measurement data.

Now the basic structures of capacitive sensors always use cylindrical fixed electrodes and the measurement for different diameter hole requires different specifications of sensor probe. For the shortfall of the measurement method for hole profile with capacitive sensor, this paper introduces the principle of capacitive sensor for micro/mini hole measurement and the capacitance-based device used in different diameter micro/mini holes’ profile measurement through the structural improvements of the capacitive sensor probe, then simulation and error analysis are conducted. The simulation results indicate the error is less than 5%, and it verifies the feasibility of the profile measurement principle for different diameter hole with capacitance sensor.

Non-invasive measurements of blood velocity at the capillary level are of great interest in many clinical applications. Recently we presented a new method for the quantitative estimation of blood flow velocity, based on the use of the Radon transform. The technique was based on narrow band illumination at 525 nm and tracking of non-uniform distribution of red blood cells within the vessel, rather than the individual blood cells themselves. Here we present a complete error analysis of this useful technique, highlighting the role of camera and illumination choices. Finally we propose in vivo examples on retinal flow imaging and compare the results obtained with this technique to the one proposed by a commercial system.

Over the past decade, a number of information forensic techniques have been developed to identify digital image manipulation and falsification. Recent research has shown, however, that an intelligent forger can use anti-forensic countermeasures to disguise their forgeries. In this paper, an anti-forensic technique is proposed to falsify the lateral chromatic aberration present in a digital image. Lateral chromatic aberration corresponds to the relative contraction or expansion between an image's color channels that occurs due to a lens's inability to focus all wavelengths of light on the same point. Previous work has used localized inconsistencies in an image's chromatic aberration to expose cut-and-paste image forgeries. The anti-forensic technique presented in this paper operates by estimating the expected lateral chromatic aberration at an image location, then removing deviations from this estimate caused by tampering or falsification. Experimental results are presented that demonstrate that our anti-forensic technique can be used to effectively disguise evidence of an image forgery.

In the system of airborne remote sensing measurement, the optical system should meet the requirements of long focal length, large aperture, light weight and wide waveband due to the particular characteristics of usage environment and observation objects. To meet the special requirements of the optical system structure, an off-axis four-mirror reflective optical system is designed based on an off-axis three-mirror reflective optical system from modern optical design theory. The structure and principle of the off-axis four-mirror reflective system are described and the MTF curve is given in this paper. At the same time, according to the working environmental condition of the system, the temperature adaptability of the system is analyzed and the analysis results are given. Based on the results, the system error is analyzed and discussed in detail applying the precision theory. The system error for each optical component is analyzed and allocated. The qualitative analysis for the influence factors of system error is also given.

Three-flat test can separate the reference surface error from the test part surface in the surface measurement by interferometry. The solution based on mirror symmetry of three-flat test is compact and highly accurate. In practice, the error will be introduced when the position of three flats are misalignment or the relative rotation angle are not accurate. The influence of rotation angle error are simulated and discussed. Then the experiment was carried out on three reference flats and the flat surface profiles were derived by mirror symmetry method. The experiment results show good agreement and the difference is in a nanometer level.