Digital scanning converter for medical endoscopic ultrasound imaging / 生物医学工程学杂志

This paper mainly introduces the design of digital scanning converter (DSC) for medical endoscopic ultrasound imaging. Fast modified vector totational CORDIC (FMVR-CORDIC) arithmetic complete coordinate conversion is used to increase the speed of ultrasonic scanning imaging. FPGA is used as the kernel module to control data transferring, related circuits and relevant chips' working, and to accomplish data preprocessing. With the advantages of simple structure, nice flexibility and convenience, it satisfies the demand for real-time displaying in this system. Finally, the original polar coordinate image is transformed to rectangular coordinate grey image through coordinate transformation. The system performances have been validated by the experimental result.

Coded excitation circuit on medical ultrasonic endoscope imaging system / 生物医学工程学杂志

In this paper, we introduce a coded excitation circuit for medical ultrasonic endoscope imaging system. This circuit is composed of TC6320 and its drive chip. The experiment demonstrates that this circuit can export frequency-adjustable, duration-controllable coded signals, and its voltage reaches +/-60 V. It still works well when excitant frequency reaches 30 MHz. Compared with the conventional medical ultrasonic pulse-echo imaging system, this coded excitation system has the potential of higher SNR and deeper penetration depth, especially for the small emission power system. This method has a bright future.

RovoIving ultrasonic probe for medical endoscope imaging system based on USB2.0 / 生物医学工程学杂志

This paper mainly introduces the design and implementation of rotary scanning imaging for Endoscopic Ultrasonography System based on USB2.0. The ultrasonic pulse-echo imaging technique has been used. In the paper, we simply introduce the emission circuit, receiving circuit and isolation circuit. According to the character of rotary scanning, we design the synchronous control circuit based on FPGA and data transmission circuit based on USB2.0. Finally the original polar coordinate image is transformed to rectangular coordinate grey image through coordinate transformation. The system performances have been validated by the experimental result gotten by scanning a specific object with continuous rotary motor.

Motion tracking of coronary vessel segment based on active contour model / 生物医学工程学杂志

An original method for analyzing two-dimensional motion of coronary arteries from X-ray angiogram sequences based on active contour model (snake) is presented. The convergence result of the snake in previous frame is used as the initial guess in current frame. Centerlines of interesting vessel segments at successive time instants can be detected through snake deforming from its initial position to optimal position by minimizing the proper energy function. Measurement of intensity similarity between consecutive frames is encompassed into the energy function to obtain accurate tracking. The effectiveness of the method has been demonstrated on clinical coronary artery angiogram sequences and results are encouraging.

Three-dimensional moston estimation of coronary artery from single-plane cineangiogram sequences / 生物医学工程学杂志

This paper presents a method for estimating three-dimensional (3D) motion of coronary arteries from single-plane X-ray angiogram sequences on two views. Firstly, original images are preprocessed and two-dimensional (2D) vessel skeletons are extracted. 2D motion estimation is performed along the skeletons in two images. Then geometrical transformation matrix between views is obtained based on perspective projection model for X-ray angiography system, and 3D coordinate of spatial points are calculated. The 3D motion estimation and reconstruction algorithm is applied along the two image sequences to accomplish 3D reconstruction of vessel skeletons and motion vectors between consecutive time instants. Its effectiveness has been demonstrated on clinical single-plane coronary artery angiograms and potential errors are discussed.

Coronary artery motion estimation using X-ray cineangiogram / 生物医学工程学杂志

This paper presents an approach for estimating the non-rigid motion of coronary arteries using digital angiographic images. Displacement vectors of vessel points are obtained by finding points correspondences in two successive frames. Smoothness of motion field and vessel deformation measurement are considered in matching, and unmatched regions are also dealt with in the fact that the vessel after deformation may have different size with its original station. The search strategy for optimal matching is carried out using dynamic programming (DP) so that computing cost is reduced. Results of this motion estimation method applied to synthetic and clinical images have shown that the method is accurate, with a root mean square error about one pixel for simulated data. For the case of actual X-ray coronary angiographic images, visual inspection of the detected pairs of points shows that the results are very encouraging.