A content-adaptive sharpness enhancement algorithm using 2D FIR filters trained by pre-emphasis

2013 ◽  
Vol 24 (5) ◽  
pp. 579-591 ◽  
Author(s):  
Ik Hyun Choi ◽  
Yeon-Oh Nam ◽  
Byung Cheol Song
Keyword(s):  
Fir Filters ◽  
Sharpness Enhancement ◽  
2D Fir Filters ◽  
Enhancement Algorithm ◽  
Content Adaptive

scholarly journals Gaussian Circular 2D FIR Filters Designed Using Analytical Approach

2020 ◽  
Vol 16 ◽  
Keyword(s):  
Analytical Approach ◽  
Design Procedure ◽  
Peak Frequency ◽  
Fir Filters ◽  
Chebyshev Series ◽  
Analytical Design ◽  
Frequency Transformation ◽  
Low Pass ◽  
Band Pass ◽  
2D Fir Filters

This paper proposes an analytical design procedure for a particular class of 2D filters, namelyGaussian-shaped, circularly-symmetric FIR filters. We approach both low-pass and band-pass circular filters,which are adjustable in selectivity and peak frequency. The design starts from a given 1D Gaussian prototypefilter, approximated using the Chebyshev series. A frequency transformation is applied to derive the circularfilter. Several design examples are provided for both types of filters. The filters designed through this methodare efficient, their frequency response results in a factored or nested form, convenient for implementation.

An Excellent 2D Window Function

2014 ◽  
Vol 651-653 ◽  
pp. 2116-2120
Author(s):  
Yun Long Wang ◽  
Shi Hu Wang
Keyword(s):  
Matrix Equation ◽  
Window Function ◽  
Fir Filters ◽  
2D Fir Filters ◽  
Sinc Sum

In the aid of sinc sum function and matrix equation a new 2D window function is obtained. It is as simple as a 2D cosine window function. Comparison shows that the new 2D window function can provide much better 2D FIR filters than 2D Hamming window function. Maximum passband ripples are about 2.5-3.5 times smaller and maximum stopband ripples are about 1.5 times smaller with equal or very small different passband and stopband edge frequencies.

scholarly journals A Self-Reconfigurable Platform for the Implementation of 2D Filterbanks with Real and Complex-Valued Inputs, Outputs, and Filter Coefficients

VLSI Design ◽  
2014 ◽  
Vol 2014 ◽  
pp. 1-24 ◽  
Author(s):  
Daniel Llamocca ◽  
Marios Pattichis
Keyword(s):  
General Purpose ◽  
Fir Filters ◽  
One Dimensional ◽  
Dynamically Reconfigurable ◽  
Processing Times ◽  
Input And Output ◽  
Reconfigurable Platform ◽  
2D Fir Filters ◽  
Complex Valued ◽  
Real Complex

We introduce a dynamically reconfigurable 2D filterbank that supports both real and complex-valued inputs, outputs, and filter coefficients. This general purpose filterbank allows for the efficient implementation of 2D filterbanks based on separable 2D FIR filters that support all possible combinations of input and output signals. The system relies on the use of dynamic reconfiguration of real/complex one-dimensional filters to minimize the required hardware resources. The system is demonstrated using an equiripple and a Gabor filterbank and the results using both real and complex-valued input images. We summarize the performance of the system in terms of the required processing times, energy, and accuracy.

scholarly journals An Image Sharpness Enhancement Algorithm Based on Green Function

2021 ◽  
Vol 38 (2) ◽  
pp. 513-519
Author(s):  
Qiuhe Huang
Keyword(s):  
Green Function ◽  
Original Image ◽  
Subjective Effect ◽  
Image Sharpness ◽  
The Poor ◽  
Gradient Domain ◽  
Sharpness Enhancement ◽  
The Green Function ◽  
Enhancement Algorithm ◽  
Traditional Image

The traditional image sharpness enhancement algorithm faces several defects, namely, the lack of details, and the poor subjective effect. To solve these defects, this paper proposes an image sharpness enhancement algorithm based on the Green function. Specifically, the Retinex model was employed to ensure that the enhanced image has outstanding details, and the Poisson’s equation was solved to maintain the consistency between the enhanced image and the original image in the gradient domain. Then, adaptive brightness mapping was carried out to determine the boundary conditions suitable for display, and the boundary of the region was sampled to reduce the complexity of our algorithm. Experimental results show that our algorithm improved the contrast and sharpness of images from the levels of contrastive image enhancement algorithms.

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