BIT醫学图像答案2015.1.24.doc

医学图像答案 1. Image terminology explanation（医学图像术语解释） (1) image smoothing（图像平滑） Image smoothing is used to highlight the image of wide area, the low frequency component, trunk or suppress image noise and interference of high frequency components, make the image brightness flat gradient, gradient decrease mutations, improve the image quality of the image processing methods.Image smoothing methods include: interpolation method, linear smoothing method, convolution method and so on. image sharpening（图像锐化） Image sharpening is to compensate the image contour, enhancing image edge and gray level jump, images by an average or integral operation, thus on the inverse operation, make the image clear.Image sharpening method includes: gradient method and Laplace algorithm, Robert algorithm and so on. low-pass filter（低通滤波器） A low-pass filter is a filter that passes signals with a frequency lower than a certain cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency. The amount of attenuation for each frequency depends on the filter design. high-pass filter（高通滤波器） A high-pass filter is an electronic filter that passes signals with a frequency higher than a certain cutoff frequency and attenuates signals with frequencies lower than the cutoff frequency. The amount of attenuation for each frequency depends on the filter design. A high-pass filter is usually modeled as a linear time-invariant system. It is sometimes called a low-cut filter or bass-cut filter.High-pass filters have many uses, such as blocking DC from circuitry sensitive to non-zero average voltages or radio frequency devices. image restoration（图像复原） Image restoration is the operation of taking a corrupted/noisy image and estimating the clean original image. Corruption may come in many forms such as motion blur, noise, and camera misfocus. Image restoration is different from image enhancement in that the latter is designed to emphasize features of the image that make the image more plea