Real-time Color Research Articles

Color calibration of swine gastrointestinal tract images acquired by radial imaging capsule endoscope.

The type of illumination systems and color filters used typically generate varying levels of color difference in capsule endoscopes, which influence medical diagnoses. In order to calibrate the color difference caused by the optical system, this study applied a radial imaging capsule endoscope (RICE) to photograph standard color charts, which were then employed to calculate the color gamut of RICE. Color gamut was also measured using a spectrometer in order to get a high-precision color information, and the results obtained using both methods were compared. Subsequently, color-correction methods, namely polynomial transform and conformal mapping, were used to improve the color difference. Before color calibration, the color difference value caused by the influences of optical systems in RICE was 21.45±1.09 . Through the proposed polynomial transformation, the color difference could be reduced effectively to 1.53±0.07 . Compared to another proposed conformal mapping, the color difference value was substantially reduced to 1.32±0.11 , and the color difference is imperceptible for human eye because it is . Then, real-time color correction was achieved using this algorithm combined with a field-programmable gate array, and the results of the color correction can be viewed from real-time images.

一种基于FPGA的彩色图像实时增强方法

一种基于FPGA的彩色图像实时增强方法

SmartColor: Real-Time Color and Contrast Correction for Optical See-Through Head-Mounted Displays

Users of optical see-through head-mounted displays (OHMD) perceive color as a blend of the display color and the background. Color-blending is a major usability challenge as it leads to loss of color encodings and poor text legibility. Color correction aims at mitigating color blending by producing an alternative color which, when blended with the background, more closely approximates the color originally intended. In this paper we present an end-to-end approach to the color blending problem addressing the distortions introduced by the transparent material of the display efficiently and in real time. We also present a user evaluation of correction efficiency. Finally, we present a graphics library called SmartColor showcasing the use of color correction for different types of display content. SmartColor uses color correction to provide three management strategies: correction, contrast, and show-up-on-contrast. Correction determines the alternate color which best preserves the original color. Contrast determines the color which best supports text legibility while preserving as much of the original hue. Show-up-on-contrast makes a component visible when a related component does not have enough contrast to be legible. We describe SmartColor's architecture and illustrate the color strategies for various types of display content.

Abstract 16905: Evaluation of Immediate Procedural Outcome After MitraClip Using Automated Quantitaive Real-time Volume Color Flow Doppler Transesophageal Echocardiography

Background: Current echocardiographic evaluation of residual MR after Mitra-Clip is based on a semi-quantitative scale (trace to 4+). We evaluated a previously validated quantitative approach using automated real-time volume color flow Doppler (3D-RTVCFD). Methods: 30 patients (age 82 ± 5) underwent Mitra-Clip implantation guided by 3D-RTVCFD TEE (Siemens SC2000, CA). In 10 patients, data to automatically quantify 3-D regurgitant volume (RV, ml) and fraction (RF, %) and anatomic regurgitant orifice area (AROA) was available (Figure, upper panel). All patients had conventional 2-D Echo data for assessment of MR severity using the standard integrated approach. Results: MR was severe (4+) in 8, and moderately severe (3+) in 2 patients at baseline. MR post Mitra-Clip was mild or trace in 6 (≤1+, Group 1), and moderate in 4 (Group 2) patients. At baseline, the (mean±SD) 3-D RV/RF was 54.5±19.9 ml/60.6±10.2% and the AROA was 0.6±0.2 cm2 for the whole group. Post Mitra-Clip, the 3-D RV/RF was 23.6±10.3 ml/37.0±13.9% (p<0.01/p<0.001 vs. baseline) and the AROA was 0.3±0.1 cm2 (p<0.05). Both Group 1 and Group 2 had similar baseline RF, and both demonstrated a 39% and 38% decrease in RF post Mitra-clip, respectively (Figure, bottom graph). The decrease in AROA in both groups post Mitra-Clip was also significant (~53% in Group 1 and ~59% in Group 2). Thus, despite “moderate” residual MR using the semi-quantitative scale in Group 2, there was significant decreases in both RF and AROA. Conversely, in Group 1 some of the residual MR assessed as “mild” indeed had 3-D RF and AROA in the moderate range, post Mitra-clip. Conclusion: Automated quantitative 3-D real-time volume color flow Doppler TEE offers a quantitative assessment of residual MR post Mitra-clip immediately after the procedure. This may refine decision-making with regard to number of clips. Both accuracy of 3D RTVCFD TEE to quantify MR and it’s predictive value for mid- to long term procedural success need further studies.

Stereoscopic Integrated Imaging Goggles for Multimodal Intraoperative Image Guidance.

We have developed novel stereoscopic wearable multimodal intraoperative imaging and display systems entitled Integrated Imaging Goggles for guiding surgeries. The prototype systems offer real time stereoscopic fluorescence imaging and color reflectance imaging capacity, along with in vivo handheld microscopy and ultrasound imaging. With the Integrated Imaging Goggle, both wide-field fluorescence imaging and in vivo microscopy are provided. The real time ultrasound images can also be presented in the goggle display. Furthermore, real time goggle-to-goggle stereoscopic video sharing is demonstrated, which can greatly facilitate telemedicine. In this paper, the prototype systems are described, characterized and tested in surgeries in biological tissues ex vivo. We have found that the system can detect fluorescent targets with as low as 60 nM indocyanine green and can resolve structures down to 0.25 mm with large FOV stereoscopic imaging. The system has successfully guided simulated cancer surgeries in chicken. The Integrated Imaging Goggle is novel in 4 aspects: it is (a) the first wearable stereoscopic wide-field intraoperative fluorescence imaging and display system, (b) the first wearable system offering both large FOV and microscopic imaging simultaneously, (c) the first wearable system that offers both ultrasound imaging and fluorescence imaging capacities, and (d) the first demonstration of goggle-to-goggle communication to share stereoscopic views for medical guidance.

Stimulation of LH, FSH, and luteal blood flow by GnRH during the luteal phase in mares

A study was performed on the effect of a single dose per mare of 0 (n = 9), 100 (n = 8), or 300 (n = 9) of GnRH on Day 10 (Day 0 = ovulation) on concentrations of LH, FSH, and progesterone (P4) and blood flow to the CL ovary. Hormone concentration and blood flow measurements were performed at hours 0 (hour of treatment), 0.25, 0.5, 1, 2, 3, 4, and 6. Blood flow was assessed by spectral Doppler ultrasonography for resistance to blood flow in an ovarian artery before entry into the CL ovary. The percentage of the CL with color Doppler signals of blood flow was estimated from videotapes of real-time color Doppler imaging by an operator who was unaware of mare identity, hour, or treatment dose. Concentrations of LH and FSH increased (P < 0.05) at hour 0.25 and decreased (P < 0.05) over hours 1 to 6; P4 concentration was not altered by treatment. Blood flow resistance decreased between hours 0 and 1, but the decrease was greater (P < 0.05) for the 100-μg dose than for the 300-μg dose. The percentage of CL with blood flow signals increased (P < 0.05) between hours 0 and 1 with no significant difference between the 100- and 300-μg doses. The results supported the hypothesis that GnRH increases LH concentration, vascular perfusion of the CL ovary, and CL blood flow during the luteal phase; however, P4 concentration was not affected.

A Bio-Inspired AER Temporal Tri-Color Differentiator Pixel Array.

This article investigates the potential of a bio-inspired vision sensor with pixels that detect transients between three primary colors. The in-pixel color processing is inspired by the retinal color opponency that are found in mammalian retinas. Color transitions in a pixel are represented by voltage spikes, which are akin to a neuron's action potential. These spikes are conveyed off-chip by the Address Event Representation (AER) protocol. To achieve sensitivity to three different color spectra within the visual spectrum, each pixel has three stacked photodiodes at different depths in the silicon substrate. The sensor has been fabricated in the standard TSMC 90 nm CMOS technology. A post-processing method to decode events into color transitions has been proposed and implemented as a custom interface to display real-time color changes in the visual scene. Experimental results are provided. Color transitions can be detected at high speed (up to 2.7 kHz). The sensor has a dynamic range of 58 dB and a power consumption of 22.5 mW. This type of sensor can be of use in industrial, robotics, automotive and other applications where essential information is contained in transient emissions shifts within the visual spectrum.

Robust, Error-Tolerant Photometric Projector Compensation.

We propose a novel error tolerant optimization approach to generate a high-quality photometric compensated projection. The application of a non-linear color mapping function does not require radiometric pre-calibration of cameras or projectors. This characteristic improves the compensation quality compared with related linear methods if this approach is used with devices that apply complex color processing, such as single-chip digital light processing projectors. Our approach consists of a sparse sampling of the projector's color gamut and non-linear scattered data interpolation to generate the per-pixel mapping from the projector to camera colors in real time. To avoid out-of-gamut artifacts, the input image's luminance is automatically adjusted locally in an optional offline optimization step that maximizes the achievable contrast while preserving smooth input gradients without significant clipping errors. To minimize the appearance of color artifacts at high-frequency reflectance changes of the surface due to usually unavoidable slight projector vibrations and movement (drift), we show that a drift measurement and analysis step, when combined with per-pixel compensation image optimization, significantly decreases the visibility of such artifacts.

Implementation and control of a 360 degree rotating cylindrical LED full color display

This study used PIC 32MX 795F512H single-chip micro-controller unit as the control core to implement the design and production of full color LED rotating display. The display of this system is based on human vision. For the eye storage characteristic generated by high-speed dynamic images, the single-chip micro-controller unit controls single-row RGB colors LED display lamp bank, carried and rotated by a rotating platform, in order to implement the full color display of dynamic scan. This rotating full color display has three characteristics: (1) 360° surround display, so that people in any position can see colorful pictures, the information spreading efficiency is increased greatly; (2) as many as 16,777,216 colors can be displayed by using a small amount of control chips and RGB LED with dynamic scanning control technique, so as to display full color pictures; (3) the image acquisition and real-time transmission technology of this work can use camera to shoot various objects or persons. The image display codes are transmitted instantly to the single-chip micro-controller unit of console display by the self-developed image acquisition program and wireless transmission packet technology. The design of the real-time full color LED rotating display for pictures is completed by video scan technique. The test result of the self-made rotating machine shows that any picture can be displayed on the display machine completely, and the performance is good.

Development of compaction monitoring system for asphalt pavements

There is a great interest in developing and implementing new technologies for real-time evaluation of the uniformity of the construction of asphalt layers. In this study, the researchers developed a system for monitoring and documenting the compaction process of asphalt mixtures in the field. This system is called the compaction monitoring system (CMS). The CMS uses the latest global positioning system technologies and various sensors to provide full coverage of an asphalt layer. The new system can be mounted on any roller in a matter of minutes, and it provides the roller operator with real-time color displays of the number of passes of the entire mat, the compaction effectiveness, and the temperature at the first pass of the roller. This system was successfully tested in a number of field projects. The CMS was able to show some inconsistencies in the compaction process such as unequal compaction converge across the mat, non-uniform compaction effort and temperature, and delay in compaction after placement of asphalt mixtures. The compaction data are stored for post-processing analysis and evaluation. In addition, the researchers validated a proposed method for predicting the density of asphalt pavements in the field. The results showed good correlation between predicted and measured density.

Real Time Motion and Color Detection

When using HD video cameras in stores a large storage space is needed. The required&#x0D; storage space can be decreased using motion and a color detection algorithm that&#x0D; makes the camera records only when a motion or a lighting change occur. So, in this&#x0D; work a real time motion and color detection is presented based on the difference of&#x0D; two successive frames of images after dividing the image into blocks, different block&#x0D; sizes are tested (2×2, 4×4 , and 8×8).YCbCr color system is used for each case with&#x0D; different thresholds for Cb, Cr, and Y. Good results for the motion detection can be&#x0D; obtained using Cb, and Cr other than Y, since the coloring components of an image are&#x0D; exist in Cr, and Cb, which are important for motion detection. Additionally the&#x0D; components that produce or reflect bright light can be obtained from Y. Consequently&#x0D; the result of lightening change detection at different illumination conditions is better&#x0D; using Y more than Cb, and Cr. This means that the best result for both motion, and&#x0D; lighting change detection is obtained by combining the chrominance (Cb, Cr) and&#x0D; luminance (Y) components of a video. The data used in this work are collected in an&#x0D; indoor environment using a laptop webcam under different illumination conditions.

업데이트된 피부색을 이용한 얼굴 추적 시스템

*In this paper, we propose a real-time face tracking system using an adaptive face detector and a tracking algorithm. An image is divided into the regions of background and face candidate by a real-time updated skin color identifying system in order to accurately detect facial features. The facial characteristics are extracted using the five types of simple Haar-like features. The extracted features are reinterpreted by Principal Component Analysis (PCA), and the interpreted principal components are processed by Support Vector Machine (SVM) that classifies into facial and non-facial areas. The movement of the face is traced by Kalman filter and Mean shift, which use the static information of the detected faces and the differences between previous and current frames. The proposed system identifies the initial skin color and updates it through a real-time color detecting system. A similar background color can be removed by updating the skin color. Also, the performance increases up to 20% when the background color is reduced in comparison to extracting features from the entire region. The increased detection rate and speed are acquired by the usage of Kalman filter and Mean shift.

Special issue on real-time color image processing

Color perception plays an important role in object recognition and scene understanding both for humans and intelligent vision systems. Recent advances in digital color imaging and computer hardware technology have led to an explosion in the use of color images in a variety of applications including medical imaging, content-based image retrieval, biometrics, watermarking, digital inpainting, remote sensing, visual quality inspection, among many others. As a result, automated processing and analysis of color images has become an active area of research, which is witnessed by the large number of publications during the past two decades. The multivariate nature of color image data presents new challenges for researchers and practitioners as the numerous methods developed for singlechannel images are often not directly applicable to multichannel images. In addition, common scalar image processing operations often become computationally intractable when performed in high-dimensional spaces. As a result, the development of computationally practical methods for color image processing has become an important research area. The goals of this special issue are to summarize the state-of-the-art in real-time color image processing and to provide future directions for this exciting subfield of image processing. The intended audience includes researchers and professionals, who are increasingly dealing with the processing and analysis of color images and video. The special issue opens with ‘‘Design of a Shift-andAdd Based Hardware Accelerator for Color Space Conversion’’ by Li et al. The authors propose a hardware/software co-design architecture for Nios II, a 32-bit embedded processor. The architecture integrates a pipelined color space converter hardware accelerator based on a genetic algorithm and an LCD touch module. When implemented on a system-on-a-programmable-chip, the proposed architecture is capable of converting a 512 512 RGB image to YCbCr in 0:11 s. The special issue continues with seven articles on color image enhancement. In ‘‘A Simple Gray-Edge Automatic White Balance Method with FPGA Implementation,’’ Tan et al. propose a real-time automatic white balance method based on the gray-edge hypothesis. To reduce computational time, the method employs horizontal downsampling using the mean filter and gradient computation using horizontal first-order difference operator. The authors demonstrate the practicality of their approach using an FPGA implementation. In ‘‘A Full Linear 3 3 Color Correction between Images,’’ Lecca describes a fast color correction algorithm that is capable of equalizing the colors of two images of the same scene that are acquired under different illuminants and/or by different devices. The author demonstrates the performance of her approach against two state-of-the-art approaches on a variety of synthetic and real-world image databases. The method has linear time complexity in the M. E. Celebi (&) Department of Computer Science, Louisiana State University, Shreveport, LA, USA e-mail: ecelebi@lsus.edu

Editorial: Journal of Real-Time Image Processing—first issue of volume 10

The Journal of Real-Time Image Processing is entering its 10th year of publication with a steady increase in its stature in the area of image processing. The number of downloads grew to 37K? in 2014. There are currently six special issue calls for papers, which can be viewed in the back matter of this issue. In the past few years, changes have been made to the Editorial Board to incorporate the technological trends and challenges in the field of real-time image processing. In addition, to improve the geographical representation of manuscripts being submitted, changes are being made to the Advisory Board. As a first step, we are delighted to inform our readers that Professor Touradj Ebrahimi, who is a well-known researcher and technology leader with extensive experience in image processing, has kindly agreed to join the Advisory Board. It is a great pleasure to have him in our Advisory Board. The editorial board meeting of JRTIP (see Fig. 1) was recently held in San Francisco in February 2015 during the IS&T/SPIE Conference on Real-Time Image and Video Processing discussing various issues related to the journal. The outcome of this meeting will be noted in the next regular issue editorial. As indicated in the editorial of the last regular issue, the number of pages of JRTIP is now increased to 800 pages per year. This is the reason this issue has more than the normal number of pages or papers compared to the previous volumes. This increase in the number of pages is expected to ease the backlog of papers that are already on Online First and waiting to appear in print. One item to note is that considering that the number of requests for offering special issues has been steadily growing, we have put together a set of guidelines or rules to help potential guest editors with offering and conducting special issues. These guidelines can be viewed under the Call-For-Papers link at the journal website: http://static. springer.com/sgw/documents/1488308/application/pdf/Spe cialIssueGuidelines_final.pdf. It is quite helpful for all interested guest editors to read these guidelines before sending emails to the Editors-in-Chiefs regarding the offering of special issues. Before providing an overview of papers in this regular issue, it is worth pointing out that the next issue or second issue of volume 10 will be a special issue entitled ‘‘RealTime Color Image Processing’’. There are a total of 13 papers in this regular issue. The first paper by Khalvati et al. presents a technique named window memoization for software implementation of local image processing algorithms. This technique has been applied to six image processing algorithms and it is shown that speedups ranging from 1.2 to 7.9 are achieved while the total average speedup for different algorithms with different input images is 3.95. The second paper by Karas et al. provides a review of parallel algorithms for the computation of linear opening and closing morphological operations followed by an implementation comparison of four state-of-the-art algorithms. Then, the GPU implementations of two recent algorithms are described. The experimental results show that the proposed GPU implementation is suitable for real-time processing of industrial applications involving large images. The third paper by Rodriguez-Gomez et al. describes a hardware computing engine to perform background N. Kehtarnavaz (&) University of Texas at Dallas, Richardson, USA e-mail: kehtar@utdallas.edu

New Interface Design Using Accelerator Sensor for Smart Phone

Touch screen interface is inconvenient since it requires both hands. So this study suggests new interface as replacement. Smart devices use built-in acceleration sensor. Low pass filter and Kalman filter reduce noise and variability of the output of the acceleration sensor to enhance precision and certainty, which is then applied in widgets or menus to test usability and functionality through experiments. Besides, sensor-based color detector is used to realize real-time color detection of the camera output image, and to search color information of the image, which is then analyzed and inferred for face detection. With the suggested algorithm, we can detect the face image even when it is slanted. Also, real-time detection of color information depending on the environment is possible. Experiments have proven its features which are particularly strong in the changes in the environment. The suggested algorithm is useful for further studies concerning various interfaces on smartphone.

Eye Ball Movement to Control Computer Screen

The aim of this paper is to present a system for controlling the cursor position in a computer by human eye movements. Many modules have been developed to help the physical world interact with the digital world. Here we present a novel approach for Human Computer Interaction (HCI) where, we control cursor movement using a real time camera and color pointers. Our method is to use a camera and computer vision technology, such as image segmentation, background subtraction and color tracking, to control mouse tasks and we show how it can perform everything as current mouse devices can. A color pointer has been used for the object recognition and tracking, so as to implement the module without any physical contact with the system. The application has been created on matlab environment with operating system as windows 8.1. This method mainly focuses on the use of a web camera to develop a virtual human computer interaction device in a cost effective manner presents hands free interface between computer and human especially for physically disabled persons.

Real-time automatic multilevel color video thresholding using a novel class-variance criterion

Color image segmentation is a crucial preliminary task in robotic vision systems. This paper presents a novel automatic multilevel color thresholding algorithm to address this task efficiently. The proposed algorithm consists of a learning process and a multi-threshold searching process. The learning process learns the color distribution of an input video sequence in HSV color space, and the multi-threshold searching process automatically determines the optimal multiple thresholds to segment all colors-of-interest in the video based on a novel class-variance criterion. For the learning process, a simple and efficient color-distribution learning algorithm operating with a color-pixel extraction method is proposed to learn a color distribution model of all colors-of-interest in the video images, which simplifies the search for optimal thresholds for the colors-of-interest through a conventional multilevel thresholding method. For the multi-threshold searching process, a nonparametric multilevel color thresholding algorithm with an extended within-class variance criterion is proposed to automatically find the optimal upper bound and lower bound threshold values of each color channel. Experimental results validate the performance and computational efficiency of the proposed method by comparing with three existing methods, both visually and quantitatively.

Positive contrast spiral imaging for visualization of commercial nitinol guidewires with reduced heating.

BackgroundCMR-guidance has the potential to improve tissue visualization during cardiovascular catheterization procedures and to reduce ionizing radiation exposure, but a lack of commercially available CMR guidewires limits widespread adoption. Standard metallic guidewires are considered to be unsafe in CMR due to risks of RF-induced heating. Here, we propose the use of RF-efficient gradient echo (GRE) spiral imaging for reduced guidewire heating (low flip angle, long readout), in combination with positive contrast for guidewire visualization.MethodsA GRE spiral sequence with 8 interleaves was used for imaging. Positive contrast was achieved using through-slice dephasing such that the guidewire appeared bright and the background signal suppressed. Positive contrast images were interleaved with anatomical images, and real-time image processing was used to produce a color overlay of the guidewire on the anatomy. Temperature was measured with a fiber-optic probe attached to the guidewire in an acrylic gel phantom and in vivo.ResultsLeft heart catheterization was performed on swine using the real-time color overlay for procedural guidance with a frame rate of 6.25 frames/second. Using our standard Cartesian real-time imaging (flip angle 60°), temperature increases up to 50 °C (phantom) and 4 °C (in vivo) were observed. In comparison, spiral GRE images (8 interleaves, flip angle 10°) generated negligible heating measuring 0.37 °C (phantom) and 0.06 °C (in vivo).ConclusionsThe ability to use commercial metallic guidewires safely during CMR-guided catheterization could potentially expedite clinical translation of these methods.Electronic supplementary materialThe online version of this article (doi:10.1186/s12968-015-0219-9) contains supplementary material, which is available to authorized users.

Vision-Based Cooperative Pose Estimation for Localization in Multi-Robot Systems Equipped with RGB-D Cameras

We present a new vision based cooperative pose estimation scheme for systems of mobile robots equipped with RGB-D cameras. We first model a multi-robot system as an edge-weighted graph. Then, based on this model, and by using the real-time color and depth data, the robots with shared field-of-views estimate their relative poses in pairwise. The system does not need the existence of a single common view shared by all robots, and it works in 3D scenes without any specific calibration pattern or landmark. The proposed scheme distributes working loads evenly in the system, hence it is scalable and the computing power of the participating robots is efficiently used. The performance and robustness were analyzed both on synthetic and experimental data in different environments over a range of system configurations with varying number of robots and poses.

3D visualization of real-time color video sequences based on processing in wavelet-transform space

3D visualization of real-time color video sequences based on processing in wavelet-transform space