Discrete Wavelet Transform Core for Image Processing Applications

This paper presents a flexible hardware architecture for performing the Discrete Wavelet Transform (DWT) on a digital image. The proposed architecture uses a variation of the lifting scheme technique and provides advantages that include small memory requirements, fixed-point arithmetic implementation, and a small number of arithmetic computations. The DWT core may be used for image processing operations, such as denoising and image compression. For example, the JPEG2000 still image compression standard uses the Cohen-Daubechies-Favreau (CDF) 5/3 and CDF 9/7 DWT for lossless and lossy image compression respectively. Simple wavelet image denoising techniques resulted in improved images up to 27 dB PSNR. The DWT core is modeled using MATLAB and VHDL. The VHDL model is synthesized to a Xilinx FPGA to demonstrate hardware functionality. The CDF 5/3 and CDF 9/7 versions of the DWT are both modeled and used as comparisons. The execution time for performing both DWTs is nearly identical at approximately 14 clock cycles per image pixel for one level of DWT decomposition. The hardware area generated for the CDF 5/3 is around 15,000 gates using only 5% of the Xilinx FPGA hardware area, at 2.185 MHz max clock speed and 24 mW power consumption

Document Processing for Automatic Color form Dropout

Color dropout refers to the process of converting color form documents to black and white by removing the colors that are part of the blank form and maintaining only the information entered in the form. In this paper, no prior knowledge of the form type is assumed. Color dropout is performed by associating darker non-dropout colors with information that is entered in the form and needs to be preserved. The color dropout filter parameters include the color values of the non-dropout colors, e.g. black and blue, the distance metric, e.g. Euclidian, and the tolerances allowed around these colors. Color dropout is accomplished by converting pixels that have color within the tolerance sphere of the non-dropout colors to black and all others to white. This approach lends itself to high-speed hardware implementation with low memory requirements, such as an FPGA platform. Processing may be performed in RGB or a Luminance-Chrominance space, such as YCbCr. The color space transformation from RGB to YCbCr involves a matrix multiplication and the dropout filter implementation is similar in both cases. Results for color dropout processing in both RGB and YCbCr space are presented

Document Processing for Automatic Color Form Dropout

Color dropout refers to the process of converting color form documents to black and white by removing the colors that are part of the blank form and maintaining only the information entered in the form. In this paper, no prior knowledge of the form type is assumed. Color dropout is performed by associating darker non-dropout colors with information that is entered in the form and needs to be preserved. The color dropout filter parameters include the color values of the non-dropout colors, e.g. black and blue, the distance metric, e.g. Euclidian, and the tolerances allowed around these colors. Color dropout is accomplished by converting pixels that have color within the tolerance sphere of the non-dropout colors to black and all others to white. This approach lends itself to high-speed hardware implementation with low memory requirements, such as an FPGA platform. Processing may be performed in RGB or a Luminance-Chrominance space, such as YC bCr. The color space transformation from RGB to YC bCr involves a matrix multiplication and the dropout filter implementation is similar in both cases. Results for color dropout processing in both RGB and YC bCr space are presented

In Proceedings SPIE Human Vision and Electronic Imaging V, Jan. 2000. Evaluation of image appeal in consumer photography

In consumer photography, image appeal may be defined by the interest that a picture generates when viewed by third-party observers. In this paper, the results of a ground truth experiment on human estimation of image appeal are reported, where 11 participants were asked to rank pictures in 30 groups based on their relative appeal within their group and comment on the factors that influenced their decisions. Based on their responses, a list of both positive and negative influences was compiled and influences were grouped in general categories that include people, composition, subject, and objective metrics. The results of our experiment indicate that image appeal is related to image quality only with respect to the influences in the category of objective metrics, while the majority of influences belong to the categories of people, composition and subject. The influences in these categories are scene dependent and fundamentally different in nature from traditional image quality metrics. Thus, when evaluating image appeal a new set of metrics needs to be developed. Individual influences and their relative merits are discussed

Statistical estimation of fluid flow: an image restoration approach

Summarization: This paper focuses on Fluid Motion-Field Estimation from video data, which is a useful but challenging problem in environmental monitoring. Rivers are often monitored by flashy hydrographs that exhibit characteristic response times ranging from minutes to hours. In order to estimate the river discharge during a flush flood event, the temporary motion vector field of the river surface is needed. This paper presents a new approach in statistical estimation of fluid flow that calculates a local flow probability distribution function in the frequency domain. Our work improves upon the inefficiencies of spatial estimation of the auto-regressive STAR model and converts motion estimation into a restoration problem, where the local field can be computed fast in the frequency domain, while various natural constraints can be taken into account within the inversion strategy of the motion estimation process.Παρουσιάστηκε στο: 10th International Symposium, ISV

River flow estimation using video data

Summarization: An image-based framework for river flow monitoring based on a statistical estimation technique for fluid flow estimation is presented. This approach uses subsequent gray-scale video frames along with a statistical estimation method to extract the optical flow. An average velocity estimate is computed using the velocity vectors of the main motion trend, which is extracted using classification methods. The corresponding real-world surface velocity is computed using velocity-area transformations. The use of only two subsequent video frames and the lack of tracers in the flow are the key features of this technique in order to extract an accurate estimate of the real surface velocity. We compare our real-world surface velocity estimate with traditional current meter measurements, made on the site of Pinios river, Thessaly, Greece using the Q-liner 2 Doppler device.Παρουσιάστηκε στο: International Conference on Imaging Systems and Techniques (IST

High frequency monitoring system for integrated water resources management of rivers

Summarization: Hydrologic and geochemical processes that take place in Mediterranean watersheds have variable temporal and spatial scales. The hydrographs of both temporary and permanent rivers are flashy with response times ranging from minutes to hours. After dry periods, the first flash floods carry significant quantities of suspended solids and pollutants. Usually, scientists are not in the field during a flash flood, since these events have a short duration and are happening under adverse conditions. In other words, pollution is passing by and there is no one there to measure it. We propose to develop and implement an intelligent integrated monitoring system, utilizing electrochemical and optical sensors, for the physical (flow, suspended solids, and temperature) and chemical (conductivity, dissolved oxygen, nitrates, pH and heavy metals) parameters of the river. The data from the optical sensors will be analyzed in-situ with special pattern recognition algorithms, in order to estimate the river flow velocity field and discharge as well as the distribution of suspended solids using the hue values of the pictures. This system will be comprised of the sensors, CPU units, storage devices and a telecommunication system for data transmission. The system will be sending only the required processed data, rather than raw data, to a central station where the data will be used in an on-line integrated water resources management model. The proposed work will be accomplished with six work packages: system requirements and specifications, development of a physico-chemical monitoring subsystem, development of an optical measurements subsystem, implementation of data mining, system integration and project management, and publicity. We will develop and test the proposed system in two rivers, Koiliaris River in Crete and Acheloos River in Western Greece. The collected data will be used to assess and model the hydrologic, suspended solids and chemical loads in the two rivers.Παρουσιάστηκε στο: 1st EWaS-MED International Conference, “Improving Efficiency of Water Systems in a Changing natural and financial Environment