The Experts below are selected from a list of 15483 Experts worldwide ranked by ideXlab platform

Khan A Wahid - One of the best experts on this subject based on the ideXlab platform.

  • Automated Adaptive Brightness in Wireless Capsule Endoscopy Using Image Segmentation and Sigmoid Function
    IEEE Transactions on Biomedical Circuits and Systems, 2016
    Co-Authors: Ravi Shrestha, Shahed K. Mohammed, Md. Mehedi Hasan, Xuechao Zhang, Khan A Wahid
    Abstract:

    Wireless capsule endoscopy (WCE) plays an important role in the diagnosis of gastrointestinal (GI) diseases by capturing images of human small intestine. Accurate diagnosis of endoscopic images depends heavily on the quality of captured images. Along with image and frame rate, brightness of the image is an important parameter that influences the image quality which leads to the design of an efficient illumination system. Such design involves the choice and placement of proper light source and its ability to illuminate GI surface with proper brightness. Light emitting diodes (LEDs) are normally used as sources where modulated pulses are used to control LED's brightness. In practice, instances like under- and over-illumination are very common in WCE, where the former provides dark images and the later provides bright images with high power consumption. In this paper, we propose a low-power and efficient illumination system that is based on an automated brightness algorithm. The scheme is adaptive in nature, i.e., the brightness level is controlled automatically in real-time while the images are being captured. The captured images are segmented into four equal regions and the brightness level of each region is calculated. Then an adaptive Sigmoid Function is used to find the optimized brightness level and accordingly a new value of duty cycle of the modulated pulse is generated to capture future images. The algorithm is fully implemented in a capsule prototype and tested with endoscopic images. Commercial capsules like Pillcam and Mirocam were also used in the experiment. The results show that the proposed algorithm works well in controlling the brightness level accordingly to the environmental condition, and as a result, good quality images are captured with an average of 40% brightness level that saves power consumption of the capsule.

  • color enhancement in endoscopic images using adaptive Sigmoid Function and space variant color reproduction
    Computational and Mathematical Methods in Medicine, 2015
    Co-Authors: Mohammad S Imtiaz, Khan A Wahid
    Abstract:

    Modern endoscopes play an important role in diagnosing various gastrointestinal (GI) tract related diseases. The improved visual quality of endoscopic images can provide better diagnosis. This paper presents an efficient color image enhancement method for endoscopic images. It is achieved in two stages: image enhancement at gray level followed by space variant chrominance mapping color reproduction. Image enhancement is achieved by performing adaptive Sigmoid Function and uniform distribution of Sigmoid pixels. Secondly, a space variant chrominance mapping color reproduction is used to generate new chrominance components. The proposed method is used on low contrast color white light images (WLI) to enhance and highlight the vascular and mucosa structures of the GI tract. The method is also used to colorize grayscale narrow band images (NBI) and video frames. The focus value and color enhancement factor show that the enhancement level in the processed image is greatly increased compared to the original endoscopic image. The overall contrast level of the processed image is higher than the original image. The color similarity test has proved that the proposed method does not add any additional color which is not present in the original image. The algorithm has low complexity with an execution speed faster than other related methods.

  • image enhancement and space variant color reproduction method for endoscopic images using adaptive Sigmoid Function
    International Conference of the IEEE Engineering in Medicine and Biology Society, 2014
    Co-Authors: Mohammad S Imtiaz, Khan A Wahid
    Abstract:

    This paper presents an image enhancement and space-variant color reproduction method based on adaptive Sigmoid Function for endoscopic image. At first, using YCBCR conversion matrix, the color image is separated into luminance and chrominance components. The adaptive Sigmoid Function with two controlling parameters is applied on the uniformly distributed luminance pixels. The space-variant color reproduction generates new chrominance components by transferring and modifying old chrominance based on texture information. Finally, new luminance and chrominance components are converted into RGB color image. The proposed method highlights some of the tissue and vascular characteristics as well as pit patterns in lesion and polyp. The performance of the proposed scheme is compared with other related methods in terms of image quality, focus value, efficiency of color reproduction and statistic of visual representation.

  • EMBC - Image enhancement and space-variant color reproduction method for endoscopic images using adaptive Sigmoid Function.
    Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Inte, 2014
    Co-Authors: Mohammad S Imtiaz, Khan A Wahid
    Abstract:

    This paper presents an image enhancement and space-variant color reproduction method based on adaptive Sigmoid Function for endoscopic image. At first, using YCBCR conversion matrix, the color image is separated into luminance and chrominance components. The adaptive Sigmoid Function with two controlling parameters is applied on the uniformly distributed luminance pixels. The space-variant color reproduction generates new chrominance components by transferring and modifying old chrominance based on texture information. Finally, new luminance and chrominance components are converted into RGB color image. The proposed method highlights some of the tissue and vascular characteristics as well as pit patterns in lesion and polyp. The performance of the proposed scheme is compared with other related methods in terms of image quality, focus value, efficiency of color reproduction and statistic of visual representation.

Mohammad S Imtiaz - One of the best experts on this subject based on the ideXlab platform.

  • color enhancement in endoscopic images using adaptive Sigmoid Function and space variant color reproduction
    Computational and Mathematical Methods in Medicine, 2015
    Co-Authors: Mohammad S Imtiaz, Khan A Wahid
    Abstract:

    Modern endoscopes play an important role in diagnosing various gastrointestinal (GI) tract related diseases. The improved visual quality of endoscopic images can provide better diagnosis. This paper presents an efficient color image enhancement method for endoscopic images. It is achieved in two stages: image enhancement at gray level followed by space variant chrominance mapping color reproduction. Image enhancement is achieved by performing adaptive Sigmoid Function and uniform distribution of Sigmoid pixels. Secondly, a space variant chrominance mapping color reproduction is used to generate new chrominance components. The proposed method is used on low contrast color white light images (WLI) to enhance and highlight the vascular and mucosa structures of the GI tract. The method is also used to colorize grayscale narrow band images (NBI) and video frames. The focus value and color enhancement factor show that the enhancement level in the processed image is greatly increased compared to the original endoscopic image. The overall contrast level of the processed image is higher than the original image. The color similarity test has proved that the proposed method does not add any additional color which is not present in the original image. The algorithm has low complexity with an execution speed faster than other related methods.

  • image enhancement and space variant color reproduction method for endoscopic images using adaptive Sigmoid Function
    International Conference of the IEEE Engineering in Medicine and Biology Society, 2014
    Co-Authors: Mohammad S Imtiaz, Khan A Wahid
    Abstract:

    This paper presents an image enhancement and space-variant color reproduction method based on adaptive Sigmoid Function for endoscopic image. At first, using YCBCR conversion matrix, the color image is separated into luminance and chrominance components. The adaptive Sigmoid Function with two controlling parameters is applied on the uniformly distributed luminance pixels. The space-variant color reproduction generates new chrominance components by transferring and modifying old chrominance based on texture information. Finally, new luminance and chrominance components are converted into RGB color image. The proposed method highlights some of the tissue and vascular characteristics as well as pit patterns in lesion and polyp. The performance of the proposed scheme is compared with other related methods in terms of image quality, focus value, efficiency of color reproduction and statistic of visual representation.

  • EMBC - Image enhancement and space-variant color reproduction method for endoscopic images using adaptive Sigmoid Function.
    Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Inte, 2014
    Co-Authors: Mohammad S Imtiaz, Khan A Wahid
    Abstract:

    This paper presents an image enhancement and space-variant color reproduction method based on adaptive Sigmoid Function for endoscopic image. At first, using YCBCR conversion matrix, the color image is separated into luminance and chrominance components. The adaptive Sigmoid Function with two controlling parameters is applied on the uniformly distributed luminance pixels. The space-variant color reproduction generates new chrominance components by transferring and modifying old chrominance based on texture information. Finally, new luminance and chrominance components are converted into RGB color image. The proposed method highlights some of the tissue and vascular characteristics as well as pit patterns in lesion and polyp. The performance of the proposed scheme is compared with other related methods in terms of image quality, focus value, efficiency of color reproduction and statistic of visual representation.

Majid Ahmadi - One of the best experts on this subject based on the ideXlab platform.

  • Efficient hardware implementation of the hyperbolic tangent Sigmoid Function
    2009 IEEE International Symposium on Circuits and Systems, 2009
    Co-Authors: Ashkan H. Hosseinzadeh Namin, Karl Leboeuf, Roberto Muscedere, Huapeng Wu, Majid Ahmadi
    Abstract:

    Efficient implementation of the activation Function is important in the hardware design of artificial neural networks. Sigmoid, and hyperbolic tangent Sigmoid Functions are the most widely used activation Functions for this purpose. In this paper, we present a simple and efficient architecture for digital hardware implementation of the hyperbolic tangent Sigmoid Function. The proposed method employs a piecewise linear approximation as a foundation, and further improves the results using a lookup table. Our design proves to be more efficient considering area times delay as a performance metric when compared to similar proposals. VLSI implementation of the proposed design using a 0.18 mum CMOS process is also presented, which shows a 35% improvement over similar recently published architectures.

  • ISCAS - Efficient hardware implementation of the hyperbolic tangent Sigmoid Function
    2009 IEEE International Symposium on Circuits and Systems, 2009
    Co-Authors: Ashkan H. Hosseinzadeh Namin, Karl Leboeuf, Roberto Muscedere, Huapeng Wu, Majid Ahmadi
    Abstract:

    Efficient implementation of the activation Function is important in the hardware design of artificial neural networks. Sigmoid, and hyperbolic tangent Sigmoid Functions are the most widely used activation Functions for this purpose. In this paper, we present a simple and efficient architecture for digital hardware implementation of the hyperbolic tangent Sigmoid Function. The proposed method employs a piecewise linear approximation as a foundation, and further improves the results using a lookup table. Our design proves to be more efficient considering area × delay as a performance metric when compared to similar proposals. VLSI implementation of the proposed design using a 0.18µm CMOS process is also presented, which shows a 35% improvement over similar recently published architectures.

Siow Yong Low - One of the best experts on this subject based on the ideXlab platform.

  • on the optimization of Sigmoid Function for speech enhancement
    European Signal Processing Conference, 2011
    Co-Authors: Pei Chee Yong, Sven Nordholm, Hai Huyen Dam, Siow Yong Low
    Abstract:

    This paper develops a methodology to optimize Sigmoid Function parameters based on a weighted sum of two objective measures, which are the perceptual evaluation of speech quality (PESQ) measure and the log-likelihood ratio (LLR) measure. The Sigmoid Function has been investigated for speech enhancement as an alternative gain Function to the conventional MMSE Function and the spectral subtraction Function. The benefit of using this Function is that it has tunable parameters for both its slope and its mean. It also provides a potential to preserve more speech signal at high SNR level. The SNR estimate and the gain Function impact the value of the objective measures such as PESQ and LLR, and provide varying subjective quality. Thus, by studying the relationship between the SNR estimate and the gain Function, the performance of a single channel speech enhancement scheme can be optimized. Here, we aim to optimize the parameters of Sigmoid Function for different types of noise conditions and SNRs. Subjective listening tests demonstrate a significant improvement in the objective measures with proper choice of parameters.

  • EUSIPCO - On the optimization of Sigmoid Function for speech enhancement
    2011
    Co-Authors: Pei Chee Yong, Sven Nordholm, Hai Huyen Dam, Siow Yong Low
    Abstract:

    This paper develops a methodology to optimize Sigmoid Function parameters based on a weighted sum of two objective measures, which are the perceptual evaluation of speech quality (PESQ) measure and the log-likelihood ratio (LLR) measure. The Sigmoid Function has been investigated for speech enhancement as an alternative gain Function to the conventional MMSE Function and the spectral subtraction Function. The benefit of using this Function is that it has tunable parameters for both its slope and its mean. It also provides a potential to preserve more speech signal at high SNR level. The SNR estimate and the gain Function impact the value of the objective measures such as PESQ and LLR, and provide varying subjective quality. Thus, by studying the relationship between the SNR estimate and the gain Function, the performance of a single channel speech enhancement scheme can be optimized. Here, we aim to optimize the parameters of Sigmoid Function for different types of noise conditions and SNRs. Subjective listening tests demonstrate a significant improvement in the objective measures with proper choice of parameters.

Ashkan H. Hosseinzadeh Namin - One of the best experts on this subject based on the ideXlab platform.

  • Efficient hardware implementation of the hyperbolic tangent Sigmoid Function
    2009 IEEE International Symposium on Circuits and Systems, 2009
    Co-Authors: Ashkan H. Hosseinzadeh Namin, Karl Leboeuf, Roberto Muscedere, Huapeng Wu, Majid Ahmadi
    Abstract:

    Efficient implementation of the activation Function is important in the hardware design of artificial neural networks. Sigmoid, and hyperbolic tangent Sigmoid Functions are the most widely used activation Functions for this purpose. In this paper, we present a simple and efficient architecture for digital hardware implementation of the hyperbolic tangent Sigmoid Function. The proposed method employs a piecewise linear approximation as a foundation, and further improves the results using a lookup table. Our design proves to be more efficient considering area times delay as a performance metric when compared to similar proposals. VLSI implementation of the proposed design using a 0.18 mum CMOS process is also presented, which shows a 35% improvement over similar recently published architectures.

  • ISCAS - Efficient hardware implementation of the hyperbolic tangent Sigmoid Function
    2009 IEEE International Symposium on Circuits and Systems, 2009
    Co-Authors: Ashkan H. Hosseinzadeh Namin, Karl Leboeuf, Roberto Muscedere, Huapeng Wu, Majid Ahmadi
    Abstract:

    Efficient implementation of the activation Function is important in the hardware design of artificial neural networks. Sigmoid, and hyperbolic tangent Sigmoid Functions are the most widely used activation Functions for this purpose. In this paper, we present a simple and efficient architecture for digital hardware implementation of the hyperbolic tangent Sigmoid Function. The proposed method employs a piecewise linear approximation as a foundation, and further improves the results using a lookup table. Our design proves to be more efficient considering area × delay as a performance metric when compared to similar proposals. VLSI implementation of the proposed design using a 0.18µm CMOS process is also presented, which shows a 35% improvement over similar recently published architectures.