Su-Ling Lee

A back lighting color image enhancement method using color saturation and image fusion

In this paper, a back lighting color image enhancement method using color saturation and image fusion is presented. First, the saturation component of color image is computed by using HSV or HSI color space. Then, two different exposed images are generated by using weighting function method. Next, the enhanced image is obtained by fusing input color image and two different exposed images. Finally, several numerical examples are demonstrated to show the effectiveness of the proposed enhancement method.

Secure single-side-band signal generation using two fractional Hilbert transformers

In this paper, a secure single-side-band (SSB) generation using two fractional Hilbert transformers (FHT) is presented. First, the SSB signal generation methods using conventional Hilbert transformer (HT) and one FHT are reviewed. Then, to improve the security, a more secure SSB generation method using two FHTs is proposed. The phase angles of two FHTs can be used as the secure keys for construction and reconstruction. Finally, a numerical example is illustrated to show the effectiveness of the proposed method.

Image sharpening using matrix Riesz fractional order differentiator and discrete sine transform

In this paper, the design of matrix Riesz fractional order differentiator (FOD) using discrete sine transform (DST) is presented. First, the matrix Riesz FOD design problem is described. Then, the transfer matrix of the matrix Riesz FOD is obtained by using DST. Next, the designed matrix Riesz FOD is applied to develop an image sharpening algorithm. Finally, an example is presented to show the usefulness of the proposed DST-based matrix Riesz FOD method.

Design of matrix second-order differentiator for image sharpening using discrete sine transform

In this paper, the design of matrix second-order differentiator (SOD) using discrete sine transform (DST) is presented. First, the design problem of matrix filter is described. Then, the DST is applied to obtain the closed-form transfer matrix of the matrix SOD. Next, the designed matrix SOD is used to develop an image sharpening algorithm by using Laplacian operator. Finally, the performance of the proposed matrix SOD is evaluated through numerical examples.

A sampling rate increasing method using matrix low-pass filter and discrete cosine transform

In this paper, the design of matrix low-pass filter using discrete cosine transform (DCT) is presented. First, the matrix low-pass filter design problem is described. Then, the transfer matrix of the matrix low-pass filter is obtained by using DCT. Next, the designed matrix low-pass filter is applied to develop a sampling rate increasing method. Finally, a digital image magnification application is presented to show the effectiveness of the proposed matrix low-pass filter method.

Design of fractional hilbert transformer using fractional sample delay

In this paper, the design of fractional Hilbert transformer (FHT) using fractional sample delay (FSD) is investigated. First, the design problem of FHT is described. Then, the relation between FHT and FSD is studied such that conventional FSD design methods can be employed to design FHT directly. Finally, one numerical example is presented to show the usefulness of the proposed design method.

Design of graph filter in ill-posed condition using Tikhonov regularization

In this paper, the design of graph filter in ill-posed condition using Tikhonov regularization method is presented. First, the design problem of graph filter is described. Then, the Tikhonov regularization method is used to determine the filter coefficients. Because the explicit solution is obtained, it is easily computed and used in the applications. Finally, a numerical example for graph filter design of Markov chain data is illustrated to show the effectiveness of the proposed method.

Digital color image sharpening using Riesz potential

In this paper, a digital image sharpening algorithm is presented by using Riesz potential. First, the definition of Riesz potential is reviewed briefly. Then, the sharpened image is obtained by adding the original image to the scaling Riesz potential of image. Finally, the gray-level and color digital images are used to show the effectiveness of the proposed digital image sharpening method based on Riesz potential.