数字图像打印

(1) 名词解释RGB Red Green Blue，红绿蓝三原色CMYK Cyan Magenta yellow blacK , 青、品红、黄、黑，用于印刷的四分色HIS Horizontal Situation Indicator 水平位置指示器FFT Fast Fourier Transform Algorithm (method) 快速傅氏变换算法CWT continuous wavelet transform 连续小波变换DCT Discrete Cosine Transform 离散余弦变换DWT DiscreteWaveletTransform 离散小波变换CCD Charge Coupled Device 电荷耦合装置Pixel: a digital image is composed of a finite number of elements,each of which has a particular lication and value,these elements are called pixel像素DC component in frequency domain 频域直流分量GLH Gray Level Histogram 灰度直方图Mather(basic)wavelet：a function (wave) used to generate a set of wavelets, 母小波，用于产生小波变换所需的一序列子小波Basis functions basis image:there is only one set of αk for any given f(x), then the ψk (x) are called basis functions基函数基图像Multi-scale analysis 多尺度分析Gaussian function:is a function of the form: for some real constants a 0, b, c 0, and e ≈ 2.718281828 (Euler’s number).对于一些真正的常量0,b,c 0,和e≈2.718281828(欧拉数)。

高斯函数sharpening fi l ter 锐化滤波器Smoothing filter/convolution 平滑滤波器/卷积smoothing filter are used for blurring and for noise reduction平滑滤波器用于模糊处理和降低噪声/卷积Image enhancement /image restoration 图像增强和图像恢复空间域滤波Spatial domain filtering：频率域滤波Frequency domain filtering：Frequency domain filtering with a variable frequency for the signal filtering以频率作为变量对信号进行滤波空间分辨率：spatial resolution is a measure of the smallest discernible detail in an image.图像中可辨别的最小细节的度量灰度分辨率：Intensity resolution refers to the smallest discernible change in intensity level.灰度分辨率是指在灰度级中可分辨的最小变化取样sampling: Digitizing the coordinate values is called sampling.对坐标值进行数字化量化quantization：Digitizing the amplitude values is called quantization.对幅值数字化图像压缩：Image compression ,the art and science of reducing the amount of data required to represent an image.图像压缩是一种减少描绘一幅图像所需数据量的技术和科学.（2）问答题1. Cite one example of digital image processingAnswer: In the domain of medical image processing we may need to inspect a certain class of images generated by an electron microscope to eliminate bright, isolated dots that are no interest.2.Cite one example of spatial operation举一个空间操作的例子Answer:In the domain of medical image processing we may need to inspect a certain class of images generated by an electron microscope to eliminate bright, isolated dots that are no interest.3.Cite one example of frequency domain operation from the following processing result, make a general comment about ideal highpass filter (figure B) and Gaussian highpass filter(figure D)A.Original imageB.ideal highpass filterIn contrast to the ideal low pass filter, it is to let all the signals above the cutoff frequency fc without loss, and to make all the signals below the cutoff frequency of FC without loss of.C.the result of ideal highpass filterD.Gaussian highpass filterHigh pass filter, also known as "low resistance filter", it is an inhibitory spectrum of the low frequency signal and retain high frequency signal model (or device). High pass filter can make the high frequency components, while the high-frequency part of the frequency in the image of the sharp change in the gray area, which is often the edge of the object. So high pass filter can make the image get sharpening processingE.The result of Gaussian filter3.The original image, the ideal lowpass filter and Gaussian lowpass filter are shown below B nd C .D and E are the result of the either filter B or CA.Draw lines to connect the filter with their resultB.Explain the difference of the two filtersDue to excessive characteristics of the ideal low-pass filter too fast Jun, it will produce a ringing phenomenon.Over characteristics of Gauss filter is very flat, so it is not ringing4.What is the result when applying an averaging mask with the size 1X1?No change5.State the concept of the Nyquist sampling theorem from the figure belovyThe law of sampling process should be followed, also called the sampling theorem and the sampling theorem. The sampling theorem shows the relationship between the sampling frequency and the signal spectrum, and it is the basic basis of the continuous signal discretization. In analog / digital signal conversion process, when the sampling frequency fs.max greater than 2 times the highest frequency present in the signal Fmax fs.max>2fmax, sampling digital signal completely retained the information in the original signal, the general practical application assurance sampling frequency is 5 ~ 10 times higher than that of the signal of the high frequency; sampling theorem, also known as the Nyquist theorem6.A mean filter is a linear filter but a median filter is not, why?The basic principle of linear filtering is to replace the original image with the mean value of each pixel, but median filter replace the original image with the median value ofeach pixel.The value of mean and median is different.7.Fundamental Steps in images Digital image Processing 数字图像图像处理的基本步骤image acquisition—>image enhancement—>image restoration—>Color image processing—>w avelets—>compression（压缩）—>morphological processing(形态学理)—>segmentation（分割）—>representation and description（表示与描述）—>recognition（识别）8.With the chromaticity diagram bellow give a brief description to the RGB color model. Andthese three colors enough to compose all visible colors?Answer：Images represented in the RGB color model consist of three component images, onefor each primary color.These three colors enough to compose all visible colors（3）算法题1.The following matrix A is a 3*3 image and B is 3*3 Laplacian mask, what will be the resulting image? (Note that the elements beyond the border remain unchanged)2.Develop an algorithm to obtain the processing result B from original image A3.Develop an algorithm which computes the pseudocolor image processing by means of fourier tramsformAnswer：The steps of the process are as follow:(1) Multiply the input image f(x,y) by （-1）x+y to center the transform;(2) Compute the DFT of the image from (1) to get power spectrum F(u,v) of Fouriertransform.(3) Multiply by a filter function h(u,v) .(4) Compute the inverse DFT of the result in (3).(5) Obtain the real part of the result in (4).(6) Multiply the result in (5) by（-1）x+y4.Develop an algorithm to generate approximation image series shown in the following figure b** means of down sampling5.Develop an algorithm which implements frequency domain filtering by means of Fourier transform.Answer：The steps of the process are as follow:(1) Multiply the input image f(x,y) by （-1）x+y to center the transform;（1）将输入图像f（x，y）的（-1）x+y为中心的变换；(2) Compute the DFT of the image from (1) to get power spectrum F(u,v) of Fouriertransform.计算图像的DFT从（1）得到的功率谱f（u，v）的傅里叶变换。