Real-Time Imaging最新文献

Spectral imaging is becoming increasingly interesting not only for agricultural use but also for industrial applications. Wavelengths in the near infrared (NIR) range, in particular, can be used for materials classification. However, sorting paper according to quality is a very difficult task due to the close similarities between the materials. This work describes the development of a unique industrial inline material sorting system which uses the spectral imaging technique. The main functional parts and the sensor unit are described in detail. Classification methods for cellulose-based materials such as pulp, paper and cardboard will be discussed, as will hardware requirements for the industrial use of spectral imaging solutions, including adjustment and calibration techniques. The description of the software design focuses on the classification speed required.

For consumer imaging applications, multi-spectral color refers to capturing and displaying images in more than three primary colors in order to achieve color gamuts significantly larger than those produced by RGB capture and display devices. In this paper, we describe the building of a multi-camera recording system using off-the-shelf video cameras that, unlike existing multi-camera systems which rely on expensive and time consuming optical alignment of camera views, relies upon the virtual alignment of cameras performed in software and in real-time. Once images are properly aligned, the described camera system represents a recording platform that scales linearly in cost with the number of color primaries where new colors are added by simply attaching more cameras, and in this paper, we illustrate frames of the color video produced using a five camera system. The real-time aspects of this work are to both (1) collect an arbitrary number of colors simultaneously recording video at video rate and (2) synthesize and display the aligned channels on the computer screen on-line and in real time.

This paper presents a new progressive refinement algorithm for full spectral rendering. This algorithm adopts wavelet transformation to efficient represent full spectral data. To our knowledge, this is the first approach to employing such a transformation for progressive, full spectral rendering, where the radiance calculation through multiplications of two spectral functions is computed under a wavelet basis. We implemented the proposed technique for Monte Carlo direct lighting, and divide the rendering process into 9 stages (i=1–9), each of which employs the first leading 2ⁱ coefficients to produce progressive results. In the fourth progressive stage, our algorithm renders a spectral image that is 95% similar to the final non-progressive approach but only requires less than 70% of execution time. The quality of the rendered image is visually plausible being indistinguishable to those rendered by the non-progressive method. Our algorithm demonstrates features of fast convergence and high image fidelity. It is graceful, efficient, progressive, and flexible for full spectral rendering.

This paper presents an efficient post-processing/enhancement solution capable of reducing visual artifacts introduced during the image demosaicking process. Edge-sensing weights and the original color filter array data are used to detect structural elements in the captured image, and correct color components generated by the demosaicking process using adaptive, spectral model-based enhancement operations. The solution produces excellent results in terms of both objective and subjective image quality measures.

Recent advances in image analysis have shown that the application of 2-D discrete biorthogonal wavelet transform (DBWT) to digital image compression overcomes some of the barriers imposed by block-based transform coding algorithms while offering significant advantages in terms of coding gain, quality, natural compatibility with video formats requiring lower-resolution and graceful performance degradation when compressing at low bit rates. This paper reports on the design and field programmable gate array (FPGA) implementation of a non-separable 2-D DBWT architecture which is the heart of the proposed high-definition television (HDTV) compression system. The architecture adopts periodic symmetric extension at the image boundaries, therefore it conforms the JPEG-2000 standard. It computes the DBWT decomposition of an $N\times N$ image in approximately $2N^2/3$ clock cycles (ccs). Hardware implementation results based on a Xilinx Virtex-2000E FPGA chip showed that the processing of 2-D DBWT can be performed at 105 MHz providing a complete solution for the real-time computation of 2-D DBWT for HDTV compression.

A new mode selection method for intra-block coding in the H.264/MPEG-4 part 10 video-coding standard is proposed. There are nine 4×4 and four 16×16 intra-prediction modes for intra-block coding. Thus, to find the best intra-block coding mode for a 16×16 macroblock, all of the 144 (16×9) 4×4 and four 16×16 intra-modes need to be exhaustively computed and evaluated. We propose a context-based intra-mode selection method, which uses neighbors’ mode information to alleviate this large computational burden. We have experimented the effectiveness of our proposed algorithm under various conditions.

A novel progressive image transmission scheme based on the quadtree segmentation technique is introduced in this paper. A 3-level quadtree is used in the quadtree segmentation technique to partition the original image into blocks of different sizes. Image blocks of different sizes are encoded by their block mean values. The relatively addressing technique is employed to cut down the storage cost of block mean values.

In the proposed scheme, the number of image hierarchies can be adaptively selected according to the specific applications. By exploiting inter-pixel correlation and differently sized blocks for segmentation, the proposed scheme provides good image qualities at low bit rates and consumes very little computational cost in both image encoding and decoding procedures. It is quite suitable for real-time progressive image transmission.

In today's fast-paced information-driven society, the need for accurate, timely, and cost-effective data collection is very critical. Optical mark reader (OMR) systems can be used to achieve these aspects. This paper describes the development of a low-cost and high-speed OMR system prototype for marking multiple-choice questions. The novelty of this approach is the implementation of the complete system into a single low-cost Field Programmable Gate Array (FPGA) to achieve the high processing speed. Effective mark detection and verification algorithms have been developed and implemented to achieve real-time performance at low computational cost. The OMR is capable of processing a high-resolution CCD linear sensor with 3456 pixels at 5000 frame/s at the effective maximum clock rate of the sensor of 20 MHz (4×5 MHz). The performance of the prototype system is tested for different marker colours and marking methods. At the end of the paper the proposed OMR system is compared with commercially available systems and the pro and cons are discussed.