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Color Images (color + image)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Scale and skew-invariant road sign recognition

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 1 2007
Yi-Sheng Liu
Abstract A fast and robust method to detect and recognize scaled and skewed road signs is proposed in this paper. In the detection stage, the input color image is first quantized in HSV color model. Border tracing those regions with the same colors as road signs is adopted to find the regions of interest (ROI). The ROIs are then automatically adjusted to fit road sign shape models so as to facilitate detection verification even for scaled and skewed road signs in complicated scenes. Moreover, the ROI adjustment and verification are both performed only on border pixels; thus, the proposed road sign detector is fast. In the recognition stage, the detected road sign is normalized first. Histogram matching based on polar mesh is then adopted to measure the similarity between the scene and model road signs to accomplish recognition. Since histogram matching is fast and has high tolerance to distortion and deformation while contextual information can still be incorporated into it in a natural and elegant way, our method has high recognition accuracy and fast execution speed. Experiment results show that the detection rate and recognition accuracy of our method can achieve 94.2% and 91.7%, respectively. On an average, it takes only 4,50 and 10 ms for detection and recognition, respectively. Thus, the proposed method is effective, yet efficient. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 28,39, 2007 [source]

On estimation of the number of image principal colors and color reduction through self-organized neural networks

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 3 2002
A. Atsalakis
A new technique suitable for reduction of the number of colors in a color image is presented in this article. It is based on the use of the image Principal Color Components (PCC), which consist of the image color components and additional image components extracted with the use of proper spatial features. The additional spatial features are used to enhance the quality of the final image. First, the principal colors of the image and the principal colors of each PCC are extracted. Three algorithms were developed and tested for this purpose. Using Kohonen self-organizing feature maps (SOFM) as classifiers, the principal color components of each PCC are obtained and a look-up table, containing the principal colors of the PCC, is constructed. The final colors are extracted from the look-up table entries through a SOFM by setting the number of output neurons equal to the number of the principal colors obtained for the original image. To speed up the entire algorithm and reduce memory requirements, a fractal scanning subsampling technique is employed. The method is independent of the color scheme; it is applicable to any type of color images and can be easily modified to accommodate any type of spatial features. Several experimental and comparative results exhibiting the performance of the proposed technique are presented. © 2002 Wiley Periodicals, Inc. Int J Imaging Syst Technol 12, 117,127, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10019 [source]

Perceptual denoising of color images

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 3 2010
Ilka A. Netravali
Abstract Denoising of color images is a trade-off between sharpness of an image and perceived noise. We formulate a novel optimization problem that can maximize sharpness of an image while limiting the perceived noise under a model of visibility of additive random noise. We derive a closed-form expression for an optimal two-dimensional finite impulse response filter, show its uniqueness and existence, and present simulation results for black and white as well as color images. Simulation results show remarkable reduction in perceptibility of noise, while preserving sharpness. The computational burden required for the optimal filter is reduced by a new adhoc filter which is simple but has near optimal performance. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 215,222, 2010. [source]

Influence of background and surround on image color matching

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 4 2007
Lidija Mandic
Abstract In this article, the corresponding-color data for complex images reproduced on different media were obtained by simultaneous matching using an adjustment method. In our experiment printed color images and images displayed on a monitor were compared in different viewing conditions. The viewing condition varied in surround relative luminance and background. The experimental data show that surround relative luminance has little influence on color matching between printed and monitor images while changes in background modify color appearance. These results were used to evaluate different chromatic adaptation transforms (CAT). We found that for the same viewing conditions the SHARP transform shows the best agreement between the experimental and predicted data. SHARP transform can not predict accurately corresponding colors for blue and black regions. Therefore, we proposed new CAT that shows better characteristics than other transforms for cyan, green, and black colors and similar characteristics for other colors. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 244,251, 2007 [source]

On estimation of the number of image principal colors and color reduction through self-organized neural networks

Indocyanine green-fluorescent imaging of hepatocellular carcinoma during laparoscopic hepatectomy: An initial experience

ASIAN JOURNAL OF ENDOSCOPIC SURGERY, Issue 1 2010
T Ishizawa
Abstract Introduction: Laparoscopic hepatectomy has disadvantages in intraoperative diagnosis, because it offers limited visualization and palpability of the liver surface. Recently, we developed a novel fluorescent imaging technique using indocyanine green (ICG), which would enable identification of liver cancers during open hepatectomy. However, this technique has not yet been applied to laparoscopic hepatectomy. Materials and Surgical Technique: A patient with a hepatocellular carcinoma (HCC) located in Couinaud's segment II was administered ICG (0.5 mg per kg body weight) intravenous injection 5 d before surgery, as a routine liver function test. The prototype fluorescent imaging system was composed of a xenon light source and a laparoscope with a charge-coupled device camera that could filter out light with wavelengths below 810 nm. Intraoperatively, fluorescent imaging of the HCC was performed by changing color images to fluorescent images with a foot switch. Then, the fluorescing tumor was clearly identified on the visceral surface of segment II during mobilization of the left liver for resection of segments II and III. On the cut surface of the specimen, the tumor showed uniform fluorescence and was microscopically diagnosed as a well-differentiated HCC. Discussion: Laparoscopic fluorescent imaging using preoperative injection of ICG enabled real-time identification of HCC. This technique may be an easy and reliable tool to enhance the accuracy of intraoperative diagnosis during laparoscopic hepatectomy. [source]