32,909 research outputs found
Digital Image Analysis Using FloCIA Software for Ornamental Sunflower Ray Floret Color Evaluation
As an esthetic trait, ray floret color has a high importance in the development of new sunflower genotypes and their market value. Standard methodology for the evaluation of sunflower ray florets is based on International Union for the Protection of New Varieties of Plants (UPOV) guidelines for sunflower. The major deficiency of this methodology is the necessity of high expertise from evaluators and its high subjectivity. To test the hypothesis that humans cannot distinguish colors equally, six commercial sunflower genotypes were evaluated by 100 agriculture experts, using UPOV guidelines. Moreover, the paper proposes a new methodology for sunflower ray floret color classification - digital UPOV (dUPOV), that relies on software image analysis but still leaves the final decision to the evaluator. For this purpose, we created a new Flower Color Image Analysis (FloCIA) software for sunflower ray floret digital image segmentation and automatic classification into one of the categories given by the UPOV guidelines. To assess the benefits and relevance of this method, accuracy of the newly developed software was studied by comparing 153 digital photographs of F-2 genotypes with expert evaluator answers which were used as the ground truth. The FloCIA enabled visualizations of segmentation of ray floret images of sunflower genotypes used in the study, as well as two dominant color clusters, percentages of pixels belonging to each UPOV color category with graphical representation in the CIE (International Commission on Illumination) L*a*b* (or simply Lab) color space in relation to the mean vectors of the UPOV category. Precision (repeatability) of ray flower color determination was greater between dUPOV based expert color evaluation and software evaluation than between two UPOV based evaluations performed by the same expert. The accuracy of FloCIA software used for unsupervised (automatic) classification was 91.50% on the image dataset containing 153 photographs of F-2 genotypes. In this case, the software and the experts had classified 140 out of 153 of images in the same color categories. This visual presentation can serve as a guideline for evaluators to determine the dominant color and to conclude if more than one significant color exists in the examined genotype
X-Ray Image Processing and Visualization for Remote Assistance of Airport Luggage Screeners
X-ray technology is widely used for airport luggage inspection nowadays. However, the ever-increasing sophistication of threat-concealment measures and types of threats, together with the natural complexity, inherent to the content of each individual luggage make x-ray raw images obtained directly from inspection systems unsuitable to clearly show various luggage and threat items, particularly low-density objects, which poses a great challenge for airport screeners.
This thesis presents efforts spent in improving the rate of threat detection using image processing and visualization technologies. The principles of x-ray imaging for airport luggage inspection and the characteristics of single-energy and dual-energy x-ray data are first introduced. The image processing and visualization algorithms, selected and proposed for improving single energy and dual energy x-ray images, are then presented in four categories: (1) gray-level enhancement, (2) image segmentation, (3) pseudo coloring, and (4) image fusion. The major contributions of this research include identification of optimum combinations of common segmentation and enhancement methods, HSI based color-coding approaches and dual-energy image fusion algorithms —spatial information-based and wavelet-based image fusions. Experimental results generated with these image processing and visualization algorithms are shown and compared. Objective image quality measures are also explored in an effort to reduce the overhead of human subjective assessments and to provide more reliable evaluation results.
Two application software are developed − an x-ray image processing application (XIP) and a wireless tablet PC-based remote supervision system (RSS). In XIP, we implemented in a user-friendly GUI the preceding image processing and visualization algorithms. In RSS, we ported available image processing and visualization methods to a wireless mobile supervisory station for screener assistance and supervision.
Quantitative and on-site qualitative evaluations for various processed and fused x-ray luggage images demonstrate that using the proposed algorithms of image processing and visualization constitutes an effective and feasible means for improving airport luggage inspection
Implicit Ray-Transformers for Multi-view Remote Sensing Image Segmentation
The mainstream CNN-based remote sensing (RS) image semantic segmentation
approaches typically rely on massive labeled training data. Such a paradigm
struggles with the problem of RS multi-view scene segmentation with limited
labeled views due to the lack of considering 3D information within the scene.
In this paper, we propose ''Implicit Ray-Transformer (IRT)'' based on Implicit
Neural Representation (INR), for RS scene semantic segmentation with sparse
labels (such as 4-6 labels per 100 images). We explore a new way of introducing
multi-view 3D structure priors to the task for accurate and view-consistent
semantic segmentation. The proposed method includes a two-stage learning
process. In the first stage, we optimize a neural field to encode the color and
3D structure of the remote sensing scene based on multi-view images. In the
second stage, we design a Ray Transformer to leverage the relations between the
neural field 3D features and 2D texture features for learning better semantic
representations. Different from previous methods that only consider 3D prior or
2D features, we incorporate additional 2D texture information and 3D prior by
broadcasting CNN features to different point features along the sampled ray. To
verify the effectiveness of the proposed method, we construct a challenging
dataset containing six synthetic sub-datasets collected from the Carla platform
and three real sub-datasets from Google Maps. Experiments show that the
proposed method outperforms the CNN-based methods and the state-of-the-art
INR-based segmentation methods in quantitative and qualitative metrics
Parallelized Ray Casting Volume Rendering and 3D Segmentation with Combinatorial Map
Indiana University-Purdue University Indianapolis (IUPUI)Rapid development of digital technology has enabled the real-time volume rendering of scientific data, in particular large microscopy data sets. In general, volume rendering techniques project 3D discrete datasets onto 2D image planes, with the generated views being transparent and having designated color that is not necessarily "real" color. Volume rendering techniques initially require designating a processing method that assigns different colors and transparency coefficients to different regions. Then based on the "viewer" and the dataset "location," the method will determine the final imaging effect. Current popular techniques include ray casting, splatting, shear warp, and texture-based volume rendering. Of particular interest is ray casting as it permits the display of objects interior to a dataset as well as render complex objects such as skeleton and muscle. However, ray casting requires large memory and suffers from longer processing time. One way to address this is to parallelize its implementation on programmable graphic processing hardware. This thesis proposes a GPU based ray casting algorithm that can render a 3D volume in real-time application. In addition, to implementing volume rendering techniques on programmable graphic processing hardware to decrease execution times, 3D image segmentation techniques can also be utilized to increase execution speeds. In 3D image segmentation, the dataset is partitioned into smaller sized regions based on specific properties. By using a 3D segmentation method in volume rendering applications, users can extract individual objects from within the 3D dataset for rendering and further analysis. This thesis proposes a 3D segmentation algorithm with combinatorial map that can be parallelized on graphic processing units
Segmenting root systems in X-ray computed tomography images using level sets
The segmentation of plant roots from soil and other growing media in X-ray
computed tomography images is needed to effectively study the root system
architecture without excavation. However, segmentation is a challenging problem
in this context because the root and non-root regions share similar features.
In this paper, we describe a method based on level sets and specifically
adapted for this segmentation problem. In particular, we deal with the issues
of using a level sets approach on large image volumes for root segmentation,
and track active regions of the front using an occupancy grid. This method
allows for straightforward modifications to a narrow-band algorithm such that
excessive forward and backward movements of the front can be avoided, distance
map computations in a narrow band context can be done in linear time through
modification of Meijster et al.'s distance transform algorithm, and regions of
the image volume are iteratively used to estimate distributions for root versus
non-root classes. Results are shown of three plant species of different
maturity levels, grown in three different media. Our method compares favorably
to a state-of-the-art method for root segmentation in X-ray CT image volumes.Comment: 11 page
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