Biomedical subjects

H D Cheng

Publications and source records attributed to H D Cheng.

3 recordsLinked to original sources

PubMed2006

Breast ultrasound image enhancement using fuzzy logic.

Breast cancer is still a serious disease in the world. Early detection is very essential for breast cancer prevention and diagnosis. Breast ultrasound (US) imaging has been proven to be a valuable adjunct to mammography in the detection and classification of breast lesions. Because of the fuzzy and noisy nature of the US images and the low contrast between the breast cancer and tissue, it is difficult to provide an accurate and effective diagnosis. This paper presents a novel algorithm based on fuzzy logic that uses both the global and local information and has the ability to enhance the fine details of the US images while avoiding noise amplification and overenhancement. We normalize the images and then fuzzify the normalized images based on the maximum entropy principle. Edge and textural information are extracted to describe the lesion features and the scattering phenomenon of US images and the contrast ratio measuring the degree of enhancement is computed and modified. The defuzzification process is used to obtain the enhanced US images. To demonstrate the performance of the proposed approach, the algorithm was tested on 86 breast US images. Experimental results confirm that the proposed method can effectively enhance the details of the breast lesions without overenhancement or underenhancement.

Algorithms↗

PubMed1998

A novel approach to microcalcification detection using fuzzy logic technique.

Breast cancer continues to be a significant public health problem in the United States. Approximately, 182,000 new cases of breast cancer are diagnosed and 46,000 women die of breast cancer each year. Even more disturbing is the fact that one out of eight women in the United States will develop breast cancer at some point during her lifetime. Since the cause of breast cancer remains unknown, primary prevention becomes impossible. Computer-aided mammography is an important and challenging task in automated diagnosis. It has great potential over traditional interpretation of film-screen mammography in terms of efficiency and accuracy. Microcalcifications are the earliest sign of breast carcinomas and their detection is one of the key issues for breast cancer control. In this study, a novel approach to microcalcification detection based on fuzzy logic technique is presented. Microcalcifications are first enhanced based on their brightness and nonuniformity. Then, the irrelevant breast structures are excluded by a curve detector. Finally, microcalcifications are located using an iterative threshold selection method. The shapes of microcalcifications are reconstructed and the isolated pixels are removed by employing the mathematical morphology technique. The essential idea of the proposed approach is to apply a fuzzified image of a mammogram to locate the suspicious regions and to interact the fuzzified image with the original image to preserve fidelity. The major advantage of the proposed method is its ability to detect microcalcifications even in very dense breast mammograms. A series of clinical mammograms are employed to test the proposed algorithm and the performance is evaluated by the free-response receiver operating characteristic curve. The experiments aptly show that the microcalcifications can be accurately detected even in very dense mammograms using the proposed approach.

Breast Neoplasms↗

PubMed1993

A nonlinear fluid model for pulmonary blood circulation.

In this paper, we apply a quasi-one-dimensional unsteady nonlinear fluid model to study human pulmonary circulation. Eighteen generations of blood vessels composed of the branching arterial, capillary and venous distensible vessel segments make up the complete pulmonary circulation. The numerical result gives satisfactory agreement with the physiological experimental data: a dramatic pressure drop occurs in the arterioles and postcapillaries, a negative transmural pressure is shown in the postcapillary and small venous segments, a large reverse flow occurs in the main pulmonary artery during the diastolic period, and the reverse flow decreases gradually along the pulmonary tree. In the microgravity case where g = 180 cm s-2, the computation illustrated the effect of gravity force on the blood distribution in the different parts of the pulmonary circulation. The effect of gravity on the total output is not obvious. The effect of local factors which initiate the variations of the geometrical or pulmonary circulation can be stimulated quantitatively by this model. The proposal model can be very useful for clinical practice and for studying the extreme cases which are very difficult to investigate by experiments.

Arteries↗