Compact Image Research Articles

Note: Development of a compact x-ray particle image velocimetry for measuring opaque flows. II. Three-dimensional velocity field reconstruction

An x-ray particle image velocimetry (PIV) system using a cone-beam type x-ray was developed. The field of view and the spatial resolution are 36 × 24.05 mm(2) and 20 μm, respectively. The three-dimensional velocity field was reconstructed by adopting the least squares minimum residue and simultaneous multiplicative algebraic reconstruction techniques. According to a simulation study with synthetic images, the reconstructions were acceptable with 7 projections and 50 iterations. The reconstructed and supplied flow rates differed by only about 6.49% in experimental verification. The x-ray tomographic PIV system would be useful for 3D velocity field information of opaque flows.

Gradient Ordinal Signature and Fixed-Point Embedding for Efficient Near-Duplicate Video Detection

In order to meet the requirement of large scale real-time near-duplicate video detection, this paper has achieved two goals. First, this paper proposes a more compact local image descriptor which is termed as gradient ordinal signature (GOS). GOS not only has the advantages of low dimension, simplicity in computation, and high discrimination but also is invariant to mirror reflection, rotation, and scale changes. Second, applying the characteristics of the proposed GOS and combining with the embedding theory of metric spaces, this paper proposes an efficient similarity search method based on the fixed-point embedding (FE). A main advantage of FE is that its parameters have good controllability, and its performance is stable and not sensitive to dataset changes. On the whole, the goal of our approach focuses on the speed rather than the accuracy of near-duplicate video detection. We have evaluated our method on four different settings to verify the two goals. Specifically, the tests include image and video datasets, respectively, to evaluate the performance of GOS. Experimental results demonstrate the effectiveness, efficiency, and lower memory usage of GOS. Furthermore, the third test compares FE with locality sensitivity hashing. FE also shows a speed improvement of about ten times and saves more than 60% in memory usage. The fourth test demonstrates that the combination of GOS and FE for near-duplicate video detection can achieve better overall efficiency than the state-of-the-art methods.

Condylar subchondral formation of cortical bone in adolescents and young adults

We investigated subchondral formation of cortical bone in the condyles of adolescents and young adults, and looked for age-related and sex-related differences in bony formation with the aid of cone-beam computed tomography data in 1438 subjects aged between 10 and 30 years. The scans were part of the hospital's clinical protocol for patients seeking orthodontic or orthognathic treatment. No patient had signs or symptoms of temporomandibular disorders. Central images of the coronal and sagittal planes of the condyle were acquired and scored. Subchondral formation of cortical bone was seen as a high-density compact linear image, and subjects were classified into complete, partial, and no formation. Subchondral formation of cortical bone was first seen at the ages of 13–14 in boys and 12–13 in girls. Complete cortical bony formation was seen after the age of 22 years for men and 21 for women. We conclude that cortical bone begins to form around the periphery of the condyles during adolescence (12–14 years). A continuous, homogeneous, and compact cortical bony layer is established in young adults by the age of 21–22, indicating full development of the mandibular condyle. The condylar bone developed gradually and was generally fully developed a year earlier in women than men.

Construction of a 100[Hz] Sensing System of Textured Range Images and Its Application to Three Dimensional Mapping

In this paper, a compact high-speed range image sensor that can acquire a range image mapped with a color texture is constructed. The sensor consists of only commercially available products: a monochrome CCD camera, a color CCD camera, a laser projector, and two optical filters. The laser projector projects 19×19 multi-spot lights. Using the laser projector and the monochrome CCD camera with the optical filters, range images with 19×19, totally 361 points are measured. As fast as 100[Hz] measurement of a range image mapped with a color texture is achieved. Additionally, a three-dimensional (3D) mapping method using the constructed sensor is introduced. The performance of the constructed sensor and the 3D mapping method are evaluated by experiments. It is shown that the constructed sensing system can acquire 100[Hz] real-time textured range images and that it can be applied to 3D mapping by using range and color information.

Modified angular radial partitioning for edge image description in image retrieval

An angular radial partitioning (ARP) method divides an edge image into M×N partitions in order to make its compact image descriptor. However, it inherently suffers from a boundary problem that arises when edge pixels exist near the partition boundaries. Proposed is a modified ARP (mARP) to reduce degradation of retrieval performance caused by the boundary problem. For comparison, image retrieval tests have been carried out using the above two methods. The results demonstrate that the retrieval performance of the mARP is almost twice as good as that of the original one.

Compact image representation model based on both nCRF and reverse control mechanisms.

The aim of this paper is to construct a bio-inspired hierarchical neural network that could accurately represent visual images and facilitate follow-up processing. Our computational model adopted a ganglion cell (GC) mechanism with a receptive field that dynamically self-adjusts according to the characteristics of an input image. For each GC, a micro neural circuit and a reverse control circuit were developed to self-adaptively resize the receptive field. An array was also designed to imitate the layer of GCs that perform image representation. Results revealed that this GC array could represent images from the external environment with a low processing cost, and this nonclassical receptive field mechanism could substantially improve both segmentation and integration processing. This model enables automatic extraction of blocks from images, which makes multiscale representation feasible. Importantly, once an original pixel-level image was reorganized into a GC array, semantic-level features emerged. Because GCs, like symbols, are discrete and separable, this GC-grained compact representation is open to operations that can manipulate images partially and selectively. Thus, the GC-array model provides a basic infrastructure and allows for high-level image processing.

UAV based Multi-spectral Imaging System for Environmental Monitoring

Abstract An airborne multi-spectral imaging system is demonstrated for agricultural applications. A compact multi-spectral image capture system was mounted on an unmanned autonomous vehicle (UAV) and used to survey a landscape. Five spectral bands (three visible, two near infrared bands) were imaged, processed and analyzed to measure the quantity of vegetation in the scene. The UAV equipped with the multi-spectral imaging system finished the test flights successfully and the results of these experiments suggest that this type of system would be useful for agricultural applications as precision farming or crop yield management.

Extracting discriminative color features for face recognition

This paper presents a discriminative color features (DCF) method, which applies a simple yet effective color model, a novel similarity measure, and effective color feature extraction methods, for improving face recognition performance. First, the new color model is constructed according to the principle of Ockham’s razor from a number of available models that take advantage of the subtraction of the primary colors for boosting pattern recognition performance. Second, the novel similarity measure integrates both the angular and the distance information for improving upon the broadly applied similarity measures. Finally, the discriminative color features are extracted from a compact color image representation by means of discriminant analysis with enhanced generalization capabilities. Experiments on the Face Recognition Grand Challenge (FRGC) version 2 Experiment 4, which contains 12,776 training images, 16,028 controlled target images, and 8,014 uncontrolled query images, show the feasibility of the proposed method.

Electrostatic focusing Spindt-type field emitter array for an image sensor with a high-gain avalanche rushing amorphous photoconductor target

A new electrostatic focusing Spindt-type field emitter array (FEA) was simulated and fabricated to develop a compact FEA image sensor with a high-gain avalanche rushing amorphous photoconductor target. Although the conventional double-gated FEAs can generate focused electron beams by applying a lower voltage to the focusing electrode (second gate) than that of the gate electrode, the emission current drastically decreases. These experimental results show that by increasing the thickness of the gate electrode the emission current can be improved without deterioration of the focusing characteristics.

Weak-open images of locally separable metric spaces

In this paper, we prove that a space X is a weak-open compact image of a locally separable metric space if and only if X has a uniform cosmic-weak-base if and only if X is a weak-open compact image of a metric space and a locally cosmic space, and give some internal characterizations of weak-open s-images of locally separable metric spaces.

Wireless Imaging Module Assembly and Integration for Capsule Endoscopic Applications

Various breakthroughs have being made recently in Capsule endoscopy (CE). As the technology gets more matured with more clinical acceptance rate, it’s time to explore the best way for fabricating, packaging and integrating the CE. This paper will present the development of a compact high resolution image module with a VGA CMOS sensor and in house RF-Baseband IC chip for capsule endoscopic applications. The complete module, inclusive of lens, measures 11.5 mm in diameter by 28 mm in length have being able to design, fabricate and assemble. 640x260 CMOS sensor, 0201 capacitors, resistors and LEDs, are assembled onto a rigid-flex PCB with processes such as reflow heating and auto highly accurate pick and place die placement. The optical imaging module is interfaced with a RF communication unit, consisting of a base-band IC and antenna, to enable wireless transmission of dynamic image data to an external data processing and visualization unit. Animal trials produces ex-vivo GI tissue images of superior quality in terms of color saturation, contrast and resolution compared with currently available commercial capsule imaging devices.

A CMOS Image Sensor With On-Chip Image Compression Based on Predictive Boundary Adaptation and Memoryless QTD Algorithm

This paper presents the architecture, algorithm, and VLSI hardware of image acquisition, storage, and compression on a single-chip CMOS image sensor. The image array is based on time domain digital pixel sensor technology equipped with nondestructive storage capability using 8-bit Static-RAM device embedded at the pixel level. The pixel-level memory is used to store the uncompressed illumination data during the integration mode as well as the compressed illumination data obtained after the compression stage. An adaptive quantization scheme based on fast boundary adaptation rule (FBAR) and differential pulse code modulation (DPCM) procedure followed by an online, least storage quadrant tree decomposition (QTD) processing is proposed enabling a robust and compact image compression processor. A prototype chip including 64×64 pixels, read-out and control circuitry as well as an on-chip compression processor was implemented in 0.35 μm CMOS technology with a silicon area of 3.2×3.0 mm2 and an overall power of 17 mW. Simulation and measurements results show compression figures corresponding to 0.6-1 bit-per-pixel (BPP), while maintaining reasonable peak signal-to-noise ratio levels.

A CONTINUITY CHARACTERIZATION OF ASPLUND SPACES

AbstractA Banach space is an Asplund space if every continuous gauge has a point where the subdifferential mapping is Hausdorff weak upper semi-continuous with weakly compact image. This contributes towards the solution of a problem posed by Godefroy, Montesinos and Zizler.

Gamma-ray compton spectrum analysis to enhance medical imaging using wavelet transformation

Cs-137 radioactive source with 661.7 keV gamma- ray energy and Am-241 with 59.5 keV gamma-ray energy were used to study the body structure of materials by examining transmitted gamma-ray spectrum using a scintillation detector, NaI(Tl). Due to specific characteristic properties of the medium, the passing Compton broad scattering spectrum contains valuable information. It is possible to mark and to specify the Compton spectrum caused by atomic specifications of Al, Cu, bone, muscle, and lipid as interactive materials. Wavelet transforms and other multi-scale analysis functions have been used for compact signal and image representations in de-noising, compression and feature detection processing problems for about twenty years. Comparing the transmitted spectra through muscle, bone and a tumor-like (fat) and analyzing each spectrum by wavelet analysis, the differences of the medium were shown. This study is devoted to use of wavelet transform for feature extraction associated with gamma spectrum, which corresponds to image pixel, and their classification in comparison with the Haar and Rbio3.1 transforms.

Transform based spatio-temporal descriptors for human action recognition

Classic transformation methods have been widely and efficiently used in image processing areas, such as image de-noising, image segmentation, feature detection, and compression. Based on their compact signal and image representation ability, we apply the transform based techniques on the video recognition area to extract discriminative information from each given video sequence, and use the transformed coefficients as descriptors for representing and recognizing human actions in video sequences. We validate our proposed methods on the KTH and the Hollywood datasets, which have been extensively studied by a lot of researchers. The proposed descriptors, especially the wavelet transform based descriptor, yield promising results on action recognition.

Features Detection Based on a Variational Model in Sensornets

With the advent of CMOS cameras, it is now possible to make compact, cheap and low-power image sensors capable of on-board image processing. These embedded vision sensors provide a rich new sensing modality enabling new classes of wireless sensor networking applications. In order to build these applications, system designers need to overcome challenges associated with limited bandwith, limited power, group coordination and fusing of multiple camera views with various other sensory inputs. Real-time properties must be upheld if multiple vision sensors are to process data, communicate with each other and make a group decision before the measured environmental feature changes. The appearance of Wireless Multimedia Sensor Networks (WMSNs) requires a new generation technology of image processing for many applications. This paper presents a new approach to License Plate Localization(LPL) in WMSNs. We detect the license plate by a variational model that is embedded in several scalar functions. The motion of the dynamic interface is governed by nonlinear Partial Differential Equations(PDEs). Such variational models are flexible in handling complex environment and are concise in extracting plates boundaries despite of serious pollution. The cost of this method is moderate. The accuracy and efficiency of the proposed algorithm are illustrated by several numerical examples.

An imaging time-of-propagation system for charged particle identification at a super B factory

Super B factories that will further probe the flavor sector of the Standard Model and physics beyond will demand excellent charged particle identification (PID), particularly K/π separation, for momenta up to 4GeV/c, as well as the ability to operate under beam backgrounds significantly higher than current B factory experiments. We describe an Imaging Time-of-Propagation (iTOP) detector which shows significant potential to meet these requirements. Photons emitted from charged particle interactions in a Cherenkov radiator bar are internally reflected to the end of the bar, where they are collected on a compact image plane using photodetectors with fine spatial segmentation in two dimensions. Precision measurements of photon arrival time are used to enhance the two dimensional imaging, allowing the system to provide excellent PID capabilities within a reduced detector envelope. Results of the ongoing optimization of the geometric and physical properties of such a detector are presented, as well as simulated PID performance. Validation of simulations is being performed using a prototype in a cosmic ray test stand at the University of Hawaii.

Statistical Modeling in the Wavelet Domain for Compact Feature Extraction and Similarity Measure of Images

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Image feature extraction and similarity measure in feature space are active research topics. They are basic components in a content-based image retrieval (CBIR) system. In this letter, we present a new statistical model-based image feature extraction method in the wavelet domain and a novel Kullback divergence-based similarity measure. First, a Gaussian mixture model (GMM) and a more systematic generalized Gaussian mixture model (GGMM) are employed to describe the statistical characteristics of the wavelet coefficients and the model parameters are employed to construct a compact image feature space. A nontrivial expectation-maximization (EM) algorithm for the GGMM model is derived. Subsequently, a new Kullback divergence-based similarity measure with low-computation cost is derived and analyzed. The Brodatz texture image database and some other image databases are used to evaluate the retrieval performance based on the presented new methods. Experimental results indicate that the GMM and the GGMM-based image texture features are very effective in representing multiscale image characteristics and that the new methods outperforms other conventional wavelet-based methods in retrieval performance with a comparable level of computational complexity. It is also demonstrated that for image features extracted by the new statistical models, the similarity measure based on Kullback divergence is more effective than conventional similarity measures. </para>

Stationary and convergent strategies in Choquet games

If NONEMPTY has a winning strategy against EMPTY in the Choquet game on a space, the space is said to be a Choquet space. Such a winning strategy allows NONEMPTY to consider the entire finite history of previous moves before making each new move; a stationary strategy only permits NONEMPTY to consider the previous move by EMPTY. We show that NONEMPTY has a stationary winning strategy for every second countable T1 Choquet space. More generally, NONEMPTY has a stationary winning strategy for any T1 Choquet space with an open-finite basis. We also study convergent strategies for the Choquet game, proving the following results. (1) A T1 space X is the open image of a complete metric space if and only if NONEMPTY has a convergent winning strategy in the Choquet game on X. (2) A T1 space X is the compact open image of a metric space if and only if X is metacompact and NONEMPTY has a stationary convergent strategy in the Choquet game on X. (3) A T1 space X is the compact open image of a complete metric space if and only if X is metacompact and NONEMPTY has a stationary convergent winning strategy in the Choquet game on X.

640 × 480 pixel active-matrix Spindt-type field emitter array image sensor with high-gain avalanche rushing amorphous photoconductor target

A 640×480 pixel field emitter array (FEA) image sensor with a high-gain avalanche rushing amorphous photoconductor (HARP) target was fabricated and tested as a step toward the development of ultrahigh-sensitivity compact image sensors for high-definition television cameras. For this sensor, an active-matrix Spindt-type FEA integrated with scanning circuits and a magnetic electron focusing system were designed, and a 15-μm-thick-HARP target was used. The experimental results revealed that the prototype sensor had enough resolution for its pixel number and high sensitivity due to the electrons emitted from the active-matrix FEA being focused onto the HARP target.