A local adaptive weighted interpolation for deinterlacing

In this paper, a local weighted interpolation method for intra-field deinterlacing is proposed as an improved version of the DCS (deinterlacing with awareness of closeness and similarity) algorithm. The original DCS method is derived from bilateral filter which takes the local spatial closeness and pixel similarity into account when calculating the weight of interpolation. The proposed algorithm achieves three improvements: 1) instead of the line average, a more accurate interpolation filter is used to estimate the center missing pixel; 2) the center-independent interpolation method is proposed to replace the center-dependent interpolation strategy; 3) the adaptive weighted interpolation method is used to improve the accuracy of interpolation. Experimental results show that the proposed algorithm provides superior performance in terms of both objective and subjective image qualities when compared with other conventional benchmarks, including DCS algorithms with low complexity.     

基于区域划分的快速图像插值算法

图像插值是将低分辨率图像放大后提高视觉效果的有效方法,传统算法中有较简单且算法复杂度小的方法,但插值后的图像常常有锯齿边缘或者效果模糊,因而实际应用并不广泛。为克服以上缺陷,提出了一种先将图像进行区域划分,然后再进行快速图像插值的算法,既保证了算法较低的复杂度,又优化了图像显示效果,适合实际应用。     

基于薄板样条插值算法的巨幅影像分块并行处理

薄板样条函数是空间插值中的一种重要方法。对于巨幅影像数据使用薄板样条函数进行空间插值时,可能会出现运行时间太长,以及计算机内存空间不足或程序运行无响应的问题。针对这些问题,根据薄板样条函数光滑、连续的特点,基于GDAL开源函数库,提出对巨幅影像数据的分块读取,在块内利用并行技术求解线性方程组,确定薄板样条函数,最后进行空间插值的方法。结果表明,该方法可以有效的解决这些问题。     

Component-adaptive up-sampling for inter layer interpolation in scalable video coding

Scalable video coding (SVC) is a newly emerging standard to be finalized as an extension of H.264/AVC. The most attractive characters in SVC are the inter layer prediction techniques, such as Intra_BL mode. But in current SVC scheme, a uniform up-sampling filter (UUSF) is employed to magnify all components of an image, which will be very inefficient and result in a lot of redundant computational complexity. To overcome this, we propose an efficient component-adaptive up-sampling filter (CAUSF) for inter layer interpolation. In CAUSF, one character of human vision system is considered, and different up-sampling filters are assigned to different components. In particular, the six-tap FIR filter used in UUSF is kept and assigned for luminance component. But for chrominance components, a new four-tap FIR filter is used. Experimental results show that CAUSF maintains the performances of coded bit-rate and PSNR-Y without any noticeable loss, and provides significant reduction in computational complexity. Supported by China Postdoctoral Science Foundation (Grant No. 20080430454), the Key Laboratory of Geo-informatics of State Bureau of Surveying and Mapping (Grant No. 200834), the National High-Tech Research and Development Program of China (Grant No. 2007AA12Z151), and the National Basic Research Program of China (Grant No. 2006CB701303)     

基于刚体模型的视频插值去噪算法

为充分利用视频的时空联系去噪,提出了视频的刚体模型.刚体模型以线性关系组织视频的像素,结合了像素间的时域和空域关联,可以通过主色调区域划分和边缘句法匹配获得视频的刚体分解及其对应关系.基于刚体模型的插值去噪利用像素值的空域邻近性和时域稳定性联合判断插值像素的参考价值.对常用测试视频的去噪实验表明了刚体模型的正确性,基于刚体模型的插值去噪方法在视觉效果和峰值信噪比上都表现出色.     

ASIP-based reconfigurable architectures for power-efficient and real-time image/video processing

To meet both flexibility and performance requirements, particularly when implementing high-end real-time image/video processing algorithms, the paper proposes to combine the application specific instruction-set processor (ASIP) paradigm with the reconfigurable hardware one. As case studies, the design of partially reconfigurable ASIP (r-ASIP) architectures is presented for two classes of algorithms with widespread diffusion in image/video processing: motion estimation and retinex filtering. Design optimizations are addressed at both algorithmic and architectural levels. Special processor concepts used to trade-off performance versus flexibility and to enable new features of post-fabrication configurability are shown. Silicon implementation results are compared to known ASIC, DSP or reconfigurable designs; the proposed r-ASIPs stand for their better performance–flexibility figures in the respective algorithmic class.

一种新的区域图像插值算法

针对传统的3种图像插值算法在插值后分别存在灰度不连续、轮廓模糊、计算量大等问题,提出了一种新的区域插值算法。该算法先对图像依据纹理平坦或复杂进行区域的相对划分,然后根据待插值点在源图像中所属的区域对应地使用不同的插值算法。与一些典型插值算法进行仿真比较,验证了该算法在基本不改变插值精度的前提下,可以有效地降低运算时间。     

An efficient memory control method for video and image processing in digital TV

High definition (HD) and ultra-high definition (UHD) digital TV require high-resolution images and lots of data transfers between processors and memory devices often become the bottleneck of the system. Video and image signal processing usually require blocks of square or rectangular shaped pixel data for signal processing. It requires frequent precharging and activating new rows, and results in extra latencies for reading and writing pixel data in memory devices. This paper proposes an efficient memory controller for video and image processing to reduce the latencies for reading and writing blocks of pixel data. The controller stores a frame of pixel data by distributing contiguous lines of pixel data to multiple banks in sequence. Its efficiency is enhanced more with an interface protocol such as AMBA AXI in which outstanding transactions are allowed. Memory controllers according to the proposed scheme are designed and the performance and the efficiency are compared with the previous works.     

基于图像增强的灰度插值算法

针对传统彩色滤波阵列（Color Filter Array,CFA）插值算法在图像识别前一般需要对彩色图像预处理,其中包括把插值后的彩色图像转化为灰度图像、平滑内部和锐化边缘,过程较为繁琐的问题,提出一种新的基于图像增强的灰度插值算法,即在插值过程中锐化图像的边缘并平滑内部,插值结果直接是一幅灰度图像并且保证图像的几何特性不变．实验结果表明此算法的有效性．     

An efficient image interpolation increasing payload in reversible data hiding

Image interpolation is a very important branch in image processing. It is widely used in imaging world, for example, image interpolation is often used in 3-D medical image to compensate for information insufficiency during image reconstruction by simulating additional images between two-dimensional images. Reversible data hiding has become significant branch in information hiding field. Reversibility allows the original media to be completely restored without any degradation after the embedded messages have been extracted. This study proposes a high-capacity image hiding scheme by exploiting an interpolating method called Interpolation by Neighboring Pixels (INP) on Maximum Difference Values to improve the performance of data hiding scheme proposed by Jung and Yoo. The proposed scheme offers the benefits of high embedding capacity with low computational complexity and good image quality. The experimental results showed that the proposed scheme has good performance for payload up to 2.28 bpp. Moreover, the INP yields higher PSNRs than other interpolating methods such as NMI, NNI and BI.     

An adaptive window mechanism for image smoothing

Image smoothing using adaptive windows whose shapes, sizes, and orientations vary with image structure is described. Window size is increased with decreasing gradient magnitude, and window shape and orientation are adjusted in such a way as to smooth most in the direction of least gradient. Rather than performing smoothing isotropically, smoothing is performed in preferred orientations to preserve region boundaries while reducing random noise within regions. Also, instead of performing smoothing uniformly, smoothing is performed more in homogeneous areas than in detailed areas. The proposed adaptive window mechanism is tested in the context of median, mean, and Gaussian filtering, and experimental results are presented using synthetic and real images and compared with a state-of-the-art method.     

自适应窗宽的均值迁移图像跟踪算法

针对传统均值迁移跟踪算法中核函数窗宽固定使之无法满足图像中运动目标尺寸变化需要的问题，在分析目标特征零阶矩特点基础上，以其变化比作为观测量，以目标面积的变化比作为状态量，利用卡尔曼滤波器对未来帧中目标面积的变化进行预测进而获得同目标尺度变化相适应的核函数窗宽。该算法通过窗宽自适应变化，提高了跟踪精度，增强了跟踪稳定性，同时仍保证了跟踪的实时性。实验结果证明了该方法的有效性。     

Algorithmic and architectural design for real-time and power-efficient Retinex image/video processing

This paper presents novel algorithmic and architectural solutions for real-time and power-efficient enhancement of images and video sequences. A programmable class of Retinex-like filters, based on the separation of the illumination and reflectance components, is proposed. The dynamic range of the input image is controlled by applying a suitable non-linear function to the illumination, while the details are enhanced by processing the reflectance. An innovative spatially recursive rational filter is used to estimate the illumination. Moreover, to improve the visual quality results of two-branch Retinex operators when applied to videos, a novel three-branch technique is proposed which exploits both spatial and temporal filtering. Real-time implementation is obtained by designing an Application Specific Instruction-set Processor (ASIP). Optimizations are addressed at algorithmic and architectural levels. The former involves arithmetic accuracy definition and linearization of non-linear operators; the latter includes customized instruction set, dedicated memory structure, adapted pipeline, bypasses, custom address generator, and special looping structures. The ASIP is synthesized in standard-cells CMOS technology and its performances are compared to known Digital signal processor (DSP) implementations of real-time Retinex filters. As a result of the comparison, the proposed algorithmic/architectural design outperforms state-of-art Retinex-like operators achieving the best trade-off between power consumption, flexibility, and visual quality.

Locally edge-adapted distance for image interpolation based on genetic fuzzy system

This study presents a new adaptive scheme for developing kernel-based interpolation methods that simultaneously enhance spatial image resolution and preserve locally detailed edges. A new edge-adapted distance is first estimated according to local gradients information by combining fuzzy theory with genetic learning algorithm. This estimated distance is then employed in place of the original Euclidean distance in various interpolation methods. Additionally, a learning procedure based on genetic algorithm is presented to obtain crucial parameters of the fuzzy system automatically. Experimental results presented in numerical comparisons and in visual observations verify the effectiveness of the proposed adaptive framework for kernel-based interpolation methods.     

An algorithm for convexity-preserving surface interpolation

A simple and efficient method of convexity-preserving interpolation for grid data is introduced. An earlier algorithm due to Roulier (1987), based on a shape-preserving curve interpolation scheme due to McAllister and Roulier (1981), is modified to use a simpler but equivalent curve interpolation scheme described in Iqbal (1992). Numerical examples are provided to test the performance of the method with the slopes that are further improved using iterative technique to produce more visually pleasing surfaces.     

An adaptive spatial information-theoretic fuzzy clustering algorithm for image segmentation

This paper presents an adaptive spatial information-theoretic fuzzy clustering algorithm to improve the robustness of the conventional fuzzy c-means (FCM) clustering algorithms for image segmentation. This is achieved through the incorporation of information-theoretic framework into the FCM-type algorithms. By combining these two concepts and modifying the objective function of the FCM algorithm, we are able to solve the problems of sensitivity to noisy data and the lack of spatial information, and improve the image segmentation results. The experimental results have shown that this robust clustering algorithm is useful for MRI brain image segmentation and it yields better segmentation results when compared to the conventional FCM approach.     

The Weibull manifold in low-level image processing: An application to automatic image focusing

In this paper, we introduce a novel framework for low-level image processing and analysis. First, we process images with very simple, difference-based filter functions. Second, we fit the 2-parameter Weibull distribution to the filtered output. This maps each image to the 2D Weibull manifold. Third, we exploit the information geometry of this manifold and solve low-level image processing tasks as minimisation problems on point sets. For a proof-of-concept example, we examine the image autofocusing task. We propose appropriate cost functions together with a simple implicitly-constrained manifold optimisation algorithm and show that our framework compares very favourably against common autofocus methods from literature. In particular, our approach exhibits the best overall performance in terms of combined speed and accuracy.     

An adaptive machine learning algorithm for color image analysis and processing

In this paper, a new adaptive machine learning algorithm for analyzing and processing color images of natural scenes is presented. The eventual goal of this research is to obtain a mathematical training algorithm to guide the operation of an unsupervised pattern recognition and classification technique for detecting and extracting the image modes or clusters in a selected or constructed feature space. For this purpose, the peak modality of one-dimensional (1-D) image histograms is selected as the mathematical training criterion. Area, mode dispersion, approximated curvature and steepness are some of the measured quantities for a modality test. Linear discriminant function is then used to extract the detected image clusters in the feature or measurement space.     

面向屏幕拼接的数字视频插值算法及FPGA实现

针对多屏幕拼接显示系统中高分辨率、高清晰、低失真的显示需求,提出了一种基于FPGA实现的实时视频处理算法.在介绍了DVI接口屏幕拼接显示的系统结构及FPGA算法的主要功能后,针对算法处理对象具有视频像素流的特点,重点讨论了实时数字视频像素流的分割算法和基于滑动窗口的插值放大算法的实现.实验结果表明,该算法能够满足屏幕拼接显示的需求.     

基于分水岭算法的尿沉渣图像处理方法研究

医学图像处理是计算机网络和多媒体通信技术在医学上的一项具体应用,已在世界各地得到广泛的重视和应用。尿沉渣显微镜检查是临床检验的一项重要手段,对肾脏疾病的诊断治疗具有十分重要的作用。目前尿沉渣检查多采用显微镜下人工判别。利用计算机技术对临床上尿沉渣图像进行自动分析,将极大提高其临床鉴别的准确性,同时也显著降低临床检查人员的劳动强度。本文利用计算机显微技术对尿沉渣有形成分进行摄取,预处理和特征提取,实现了尿沉渣有形成分自动分割,其分割速度及可重复性都达到了医学临床的要求。