LCD motion blur reduction using fir filter banks

This paper presents the multirate and re-sampling techniques to realize a low-delay, 18-band quasi-ANSI filter bank for digital hearing aids, which not only achieves a rather low computation complexity without a significant increase in the latency, but reduces greatly the total computation complexity for sub-band signal processing followed by the filter bank, such as noise reduction as well as wide dynamic range compression (WDRC). Researches done in the literature all focused on how to reduce the computation complexity of the filter bank. In particular, with the efficient multirate and interpolated FIR (IFIR) approaches for a 10-ms, 18-band quasi-ANSI filter bank, approximately 93% of the multiplications are saved, compared that with a straightforward parallel FIR filters architecture. However, they did not consider the computation complexity of the sub-band signal processing. In this paper, we first investigate realizing the FIR filter bank efficiently by using the multirate re-sampling techniques. To reduce the complexity, the optimized re-sampling factor for each filter band is explored carefully. Then, with the resampling technique, an efficient multirate quasi-ANSI FIR filter bank architecture is proposed. Compare to the state-of-the-art quasi-ANSI filter bank, approximately 17.7% of multiplicative complexity is reduced further and, up to 25% of the total computation complexity for sub-band signal processing followed by the filter bank is saved, but with only a slight increase in latency, i.e. 13.6 ms.

In this paper, two methods for designing two-channel causal stable IIR PR filter banks are introduced. The first method makes use of model reduction and constrained optimization to obtain a causal stable IIR filter bank from the structural PR FIR filter bank proposed by Phoong et al (1995). It yields better frequency characteristics than the original FIR filter bank and avoids the dump at /spl pi//2 when allpass filters are used. Using a 1-D to 2-D transformation, a two dimensional PR IIR filter bank can readily be obtained from these prototypes. The second method is based on a constrained optimization technique using the general PR condition. Using this technique, filter banks with low system delay and flexible frequency characteristics can be designed. The technique can also be modified to design causal stable IIR dyadic wavelet bases with added regularity conditions. A number of design examples are used to demonstrate the usefulness of the proposed design methods.

Perfect reconstruction oversampled filter banks are equivalent to a particular class of frames in l/sup 2/(Z). These frames are the subject of this paper. First, the necessary and sufficient conditions of a filter bank for implementing a frame or a tight frame expansion are established, as well as a necessary and sufficient condition for perfect reconstruction using FIR filters after an FIR analysis. Complete parameterizations of oversampled filter banks satisfying these conditions are given. Further, we study the condition under which the frame dual to the frame associated with an FIR filter bank is also FIR and give a parameterization of a class of filter banks satisfying this property. Then, we focus on non-subsampled filter banks. Non-subsampled filter banks implement transforms similar to continuous-time transforms and allow for very flexible design. We investigate the relations of these filter banks to continuous-time filtering and illustrate the design flexibility by giving a procedure for designing maximally flat two-channel filter banks that yield highly regular wavelets with a given number of vanishing moments.

Publication in the conference proceedings of EUSIPCO, Trieste, Italy, 1996

We report on the development of an automated visual inspection system for liquid crystal display (LCD) modules. The system comprises a highly graphical software program, a unique image processing algorithm, a PC interface card for driving different types of LCD modules, and a universal test jig for holding these modules. The system is able to detect faulty or malfunctioning LCD modules with minimum intervention from human operator; allows testing to be carried out for evaluating the display quality such as contrast ratio; is able to create new test databases for new LCD modules; allows permanent storage/backup of test databases for each individual LCD module; and provides a friendly user interface for ease of operation. In addition, the system has the following features: different access levels for different users; an editor for creating software drivers for driving different types of LCD modules; and a graphical help facility.

An efficient two-step approach is presented for designing two-channel perfect-reconstruction linear-phase FIR filter banks. The first step involves finding a good solution by using an iterative procedure. This iterative procedure is generated by properly modifying the Lagrange-Newton method proposed by Horng and Willson (1992). In the second step, the resulting solution is then used as a good initial solution for further optimization that is carried out by the second algorithm of Dutta and Vidyasagar (1977). Several examples are included illustrating the efficiency of the proposed approach and the resulting two-channel filter banks.

A new class of two-channel biorthogonal filter banks is derived. The framework covers two useful subclasses: (i) causal stable IIR filter banks; (ii) linear phase FIR filter banks. Perfect reconstruction is structurally preserved and the structural complexity is very low. Filter banks of high frequency selectivity can be achieved by simply designing a single transfer function. Furthermore zeros of arbitrary multiplicity at aliasing frequency can be easily imposed, for the purpose of generating wavelets with regularity property. We also map the proposed 1D framework into 2D. The mapping preserves: (i) perfect reconstruction; (ii) stability in the IIR case; (iii) linear phase in the FIR case; (iv) zeros at aliasing frequency and (v) frequency characteristic of the filters. >

Purpose: The necessity of image retakes is initially determined on a preview monitor equipped with an operating system; therefore, some image blurring is only noticed later, on a high-resolution monitor. The purpose of this study is to investigate blur detection performance on radiographs via a deep learning approach compared with human observers. Approach: A total of 99 radiographs (blurry 57, nonblurry 42) were independently observed and rated by six observers using preview and diagnostic liquid crystal displays (LCDs). The deep convolution neural network (DCNN) was trained and tested using ninefold cross-validation. The average areas under the ROC curves (AUCs) were calculated for each observer with LCDs and by stand-alone DCNN for each test session and then statistically tested using a 95% confidence interval. Results: The average AUCs were 0.955 for stand-alone DCNN and 0.827 and 0.947 for human observers using preview and diagnostic LCDs, respectively. The DCNN revealed a high performance for image motion blur on digital radiographs (sensitivity 94.8%, specificity 96.8%, and accuracy 95.6%), along with the capability to detect a slight motion blur that was overlooked by human observers with a preview LCD. There were no cases of motion blur overlooked by the stand-alone DCNN, of which some were incorrectly recognized as nonblurry by human observers. Conclusions: The deep learning-based approach was capable of distinguishing slight motion blur that was unnoticeable on a preview LCD, and thus, is expected to aid the human visual system for detecting blurred images in the initial review of digital radiographs.

A new approach is presented for the design of two-channel perfect-reconstruction (PR) FIR filter banks employing linear-phase analysis and synthesis filters. The approach guarantees the designed filter bank to be PR through a set of implicit mathematical relationships. Furthermore, the approach formulates the design as an unconstrained quadratic programming problem to simultaneously optimize the frequency responses of the analysis and synthesis filters. The criterion for optimality is least-squares. The design technique is extendable to M-channel (M/spl ges/2), and this extension is currently under development.

Liquid crystal display (LCD) devices are well known to have slow response due to the physical limitations of the liquid crystals. Therefore, fast moving objects in a scene are often seen blurred on an LCD. In order to reduce motion blur, an accurate LCD model and an efficient deblurring algorithm are needed. However, existing LCD models are inadequate to reflect the human eye tracking limitation. Also, the spatial-temporal equivalence in LCD models is widely used but not proven directly in the 2D discrete spatial domain. In this paper, we study the human eye tracking limit by reviewing a number of papers in the cognitive science literature. We provide both theoretical and experimental arguments to support our findings. Also, we prove the spatial-temporal equivalence rigourously and verify the results using real video sequences.

There has been considerable interest in the design of multidimensional (MD) filter banks. MD filter banks find application in subband coding of images and video data. MD filter banks can be designed by cascading one-dimensional (1D) filter banks in the form of a tree structure. In this case, the individual analysis and synthesis filters are separable and the filter bank is called a separable filter bank. MD filter banks with nonseparable filters offer more flexibility and usually provide better performance. Nonetheless, their design is considerably more difficult than separable filter banks. The purpose of this paper is to provide an overview of developments in this field on the design techniques for MD filter banks, mostly two-dimensional (2D) filter banks. In some image coding applications, the 2D two-channel filter banks are of great importance, particularly the filter bank with diamond-shaped filters. We will present several design techniques for the 2D two-channel nonseparable filter banks. As the design of MD filters are not as tractable as that of 1D filters, we seek design techniques that do not involve direct optimization of MD filters. To facilitate this, transformations that turn a separable MD filter bank into a nonseparable one are developed. Also, transformations of 1D filter banks to MD filter banks are investigated. We will review some designs of MD filter banks using transformations. In the context of 1D filter bank design, the cosine modulated filter bank (CMFB) is well-known for its design and implementation efficiency. All the analysis filters are cosine modulated versions of a prototype filter. The design cost of the filter bank is equivalent to that of the prototype and the implementation complexity is comparable to that of the prototype plus a low-complexity matrix. The success with 1D CMFB motivate the generalization to the 2D case. We will construct the 2D CMFB by following a very close analogy of 1D case. It is well-known that the 1D lossless systems can be characterized by state space description. In 1D, the connection between the losslessness of a transfer matrix and the unitariness of the realization matrix is well-established. We will present the developments on the study of 2D lossless systems. As in 1D case, the 2D FIR lossless systems can be characterized in terms of state space realizations. We will review this, and then address the factorizability of 2D FIR lossless systems by using the properties of state space realizations.

In this work we look at the class of uniform biorthogonal FIR, IIR and hybrid filter banks with M = 2 channels. When quantization noise passes through the synthesis filter bank, it gets amplified due to the multiplication of synthesis filter norms to the quantization noise in each channel. Better compression, or higher coding gain, can be achieved if the quantization noise amplification is reduced. Scaling down of the synthesis filters to maintain the property of perfect reconstruction does not work so the analysis of the filter bank needs to be scaled up. Minimization of such amplification has been proposed earlier for FIR filter banks. We are proposing an implementable and stable coloring filter for IIR filter bank which is the optimum coloring filter for the assumed filter structure. We deal with an example of a hybrid filter bank based on all pass delay chain structure.

Liquid crystal displays (LCDs), which serve as receivers of high visual quality video, suffer from motion blur issues. One of the methods in terminating motion blur is motion compensated frame rate upconversion, which is widely adopted in LCDs. In the previous work, i.e., particle-based frame rate upconversion, the computation complexity is high while repeated operations and some improper cost evaluation setup are observed. Therefore, in this paper, hybrid frame rate upconversion is proposed with two features. First, the cost evaluation for particle-based motion trajectory calibration is modified based on the possible noise sources and video resolution variations. Second, repeated operations in particle-based motion trajectory calibration are observed. Therefore, original particle-based motion trajectory calibration is replaced by initial motion vector assignment and subsequent motion vector mapping to achieve computation complexity reduction, while the effective search range is relatively expanded. According to the experiment results, the visual quality is enhanced by 1.87 dB on average, compared with state-of-the-art unidirectional-based frame rate upconversion approaches. On the other hand, the computation complexity of the proposed design is reduced by 25-90% based on target video resolution, concluding a high visual quality and low computation complexity frame rate upconversion design.

In this paper, we are going to design the energy efficient Gaussian low pass FIR filter on spartan-6 FPGA. To make an energy efficient filter, we have used different methods in this paper like capacitance scaling, frequency scaling, and then we analysed the demand of power by Gaussian low pass FIR filter. The frequency range which is used in this paper is 1 GHz, 2GHz, 2.5GHz, 5 GHz, 10 GHz and the range of capacitance which we have used un this paper is 5pF, 10pF, 25pF, 40pF and 50 pF. An FIR filter always remnants in linear phase with the help of symmetric co-efficient and this is the very useful feature of the FIR filter for phase sensitive application like data communications etc. At present there are many different methods for communications and networking. So, in this paper, we have designed an energy efficient FIR filter and that design will faster than traditional design.

Utilizing an approximation scheme and a WLS algorithm, we present a method to design two-channel nonuniform-division filter (NDF) banks with continuous coefficients under the minimax criterion. It is shown that the optimal filter coefficients can be obtained by solving only linear equations. In conjunction with a proposed filter structure, a method is then presented to obtain the desired design result with filter coefficients taking on -1, 0, and +1 only. The effectiveness of the proposed technique is demonstrated by a simulation example.