A new method was developed to detect fish freshness nondestructively by combining electronic nose (E-nose) and tongue (E-tongue) in conjunction with chemometric methods. An E-nose nine metal oxide semiconductor gas sensors a commercial E-tongue were employed this research. Pseudosciaena crocea stored at 4 °C for different days used as experimental samples. Total viable counts (TVC) of the detected conventional method. data analyzed principal component analysis. Three-layer radial basis...

Structured light (SL) has a trade-off between acquisition time and spatial resolution. Temporally coded SL can produce 3D reconstruction with high density, yet it is not applicable to dynamic reconstruction. On the contrary, spatially works single shot, but only achieve sparse This paper aims accurate dense at same time. A speckle-based sensor presented, which consists of two cameras diffractive optical element (DOE) projector. The record images synchronously. First, speckle pattern was...

A phase unwrapping algorithm specially designed for the phase-shifting fringe projection profilometry (FPP) is proposed. It combines a revised dual-frequency projectionalgorithm and proposed background based quality guided (FB-QGPUA). Phase demodulated from high-frequency patterns partially unwrapped by that low-frequency ones. Then FB-QGPUA adopted to further unwrap phase. Influences of error on measurement are researched. Strategy select pitch given. Experiments demonstrate method very...

Camera calibration plays a crucial role in 3D measurement tasks of machine vision. In typical processes, camera parameters are iteratively optimized the forward imaging process (FIP). However, results can only guarantee minimum 2D projection errors on image plane, but not reconstruction errors. this paper, we propose universal method for calibration, which uses back (BPP). our method, model is used to obtain initial intrinsic and extrinsic with popular planar checkerboard pattern. Then,...

The reflection phenomenon exhibited by highly reflective surfaces considerably affects the quality of captured images, thereby rendering task structured light (SL) 3D reconstruction. In this paper, a polarized SL method is proposed to address reconstruction issues on high-reflectance surfaces. system we build in paper involves four-channel polarizing camera and digital processing (DLP) projector equipped with polarizer lens. built enables simultaneous acquisition four groups fringe each...

We propose an elliptical sub-aperture stitching (ESAS) method to measure the aspheric surfaces. In our method, non-null configuration is used overcome disadvantages of null testing. By adding dynamic tilt, different local nearly fringe patterns are obtained and corresponding phase data in masks extracted with negligible retrace errors. order obtain full aperture result, a algorithm developed stitch all together. firstly show principle method. Then performance proposed analyzed by simulation...

Compared with existing depth cameras, such as RGB-D, RealSense and Kinect, stripe-based structured light (SL) has the potential for micrometer-level 3D measurement; this can be attributed to its higher coding capacity. While surface texture, high-reflective region, occlusion remain some of main sources leading degraded reconstruction quality in complex objects, methods that are only based on SL cannot completely solve problems object reconstruction. In paper, we developed an advanced fusion...

Spatial structured light (SL) can achieve three-dimensional measurements with a single shot. As an important branch in the field of dynamic reconstruction, its accuracy, robustness, and density are vital importance. Currently, there is wide performance gap spatial SL between dense reconstruction (but less accurate, e.g., speckle-based SL) accurate often sparser, shape-coded SL). The central problem lies coding strategy designed features. This paper aims to improve quantity reconstructed...

A triple-frequency color fringe-projected technique is presented to measure dynamic objects. Three fringe patterns with a carrier frequency ratio of 1:3:9 are encoded in red, green, and blue channels pattern projected onto an object's surface. Bidimensional empirical mode decomposition used for decoupling the cross talk among extracting fundamental components three patterns. The unwrapped phase distribution high-frequency retrieved by three-step unwrapping strategy recover height...

High-accuracy 3D measurement based on binocular vision system is heavily dependent the accurate calibration of two rigidly-fixed cameras. In most traditional methods, stereo parameters are iteratively optimized through forward imaging process (FIP). However, results can only guarantee minimal 2D pixel errors, but not reconstruction errors. To address this problem, a simple method to calibrate rig backward projection (BPP) proposed. The position spatial point be determined separately from...

Speckle dots have the advantage of easy projection, which makes them good candidate features structured light (SL) cameras, such as Kinect v1. However, they generally yield poor accuracy due to block matching. To improve their accuracy, this paper proposes a dot-coded SL, coding information is added into dot distribution. Some are arranged regularly provide easy-to-locate corner features, while others specially designed form different shapes unique identification. A Gaussian-cross module and...

High dynamic range object has large surface reflectivity variations, which easily produces saturated and low-contrast regions in the captured images, further resulting calculation errors of gray value or phase value, then seriously affecting reconstruction accuracy. An auto-exposure-based structured light technique is proposed. In this method, relationship between noise-induced error intensity modulation first analyzed. It demonstrated that once a pixel larger than threshold, its can be...

Phase measuring deflectometry (PMD) is an effective technique for three-dimensional measurement of specular surfaces. However, the ambiguity monoscopic PMD and time-consuming searching process stereoscopic are challenges surface reconstruction. To solve it, we propose iterative reconstruction algorithm phase system free each pixel. An arbitrary seed point on accurately obtained via a coarse-to-fine optimization means without any other expensive complicate auxiliaries. Then, plane with height...

Abstract Background Globally, stroke is the third most significant cause of disability. A may produce motor, sensory, perceptual, or cognitive disorders that result in disability and affect likelihood recovery, affecting a person's ability to function. Evaluation post‐stroke critical for optimal care. Purpose Traditional methods classifying clinical motor patients use assessment interrogative measures, which are time‐consuming, complex, labor‐intensive. In response current situation, this...

Abstract Robust and accurate 3D reconstruction using a limited number of fringe patterns has posed challenge in the field structured light imaging. Unlike traditional approaches that rely on multiple patterns, only one or two makes phase recovery unwrapping difficult. To address this issue, recurrent classification neural network (RCNN) been developed, transforming tasks into unified task. First, training dataset consisting 1200 groups data was collected to generate total 38 400 samples,...

A robust stereo matching method based on a comprehensive mathematical model for color formation process is proposed to estimate the disparity map of images with noise and photometric variations. The band-pass filter DoP kernel firstly used out component images. Then log-chromaticity normalization applied eliminate influence lightning geometry. All other factors that may are removed through estimation specific cost. Performance developed evaluated by comparing some up-to-date algorithms....

Time of Flight (ToF) and stereo vision are the two major technologies for rapid depth information acquisition. The ToF sensor is able to obtain map directly at a high rate speed, but resolution accuracy relatively low. binocular means can high-accuracy disparity based on triangulation principle, its performance depends textures target surface. Therefore it an interesting research topic combine above techniques. In order carry out fusion 3D techniques, efficient calibration method...

In global stereo vision, balancing the matching efficiency and computing accuracy seems to be impossible because they contradict each other. case of a long baseline, this contradiction becomes more prominent. order solve difficult problem, paper proposes novel idea improve both in for baseline. way, reference images located between baseline image pairs are firstly chosen form new with short baselines. The relationship disparities pixels different baselines is revealed by considering...

Three-dimensional (3-D) reconstruction of a shiny surface is great challenge for existing structured light techniques because serious measurement errors will occur in image saturation regions the captured image. To this end, an adaptive microphase measuring profilometry (AMPMP) proposed. In method, optimal frequency selection strategy introduced to select frequencies phase-shifted fringe patterns. The intensity relation between projected pattern and estimated by fitting nonlinear function...

Surface mounted device-type light emitting diodes (SMD-LEDs) are commonly utilized as feature points in target-based vision measurement systems (T-VMSs) due to their high luminance. The non-uniform characteristics of said luminance introduce deviation errors image center extraction, however, which degrades the positioning precision T-VMS. In this study, we first analyzed two factors responsible for errors: deflection angle between LED's normal direction and observation direction, distance...