數(shù)字圖像處理-作業(yè)題及部分答案解析.doc

1.數(shù)字圖像與連續(xù)圖像相比具有哪些優(yōu)點?連續(xù)圖像f(x,y與數(shù)字圖像I(c,r中各量的含義是什么?它們有何聯(lián)系和區(qū)別? (To be compared with an analog image, what are the advantages of a digital image? Let f(x,y be an analog image, I(r, c be a digital image, please give explanation and comparison for defined variables: f/I, x/r, and y/c2.圖像處理可分為哪三個階段? 它們是如何劃分的?各有什么特點? (We can divide imageprocessing into 3 stages, what are they? how they are divided? What are their features?答:低級處理-低層操作,強調(diào)圖像之間的變換,是一個從圖像到圖像的過程;中級處理-中層操作,主要對圖像中感興趣的目標進行檢測和測量,從而建立對圖像的描述,是一個從圖像到數(shù)值或符號的過程;高級處理-高層操作,研究圖像中各目標的性質(zhì)和相互聯(lián)系,得出對圖像內(nèi)容含義的理解以及對原來客觀場景的解釋;3.試從結構和功能等角度分析人類視覺中最基本的幾個要素是什么?什么是馬赫帶效應? 什么是同時對比度?它們反映了什么共同問題? (According to the structure and function of the eyes, what are the basic elements in human vision? What is the Mach Band Effect? What is Simultaneous Contrast? What common facts can we infer from both Mach Band Effect and Simultaneous Contrast?答:人的視覺系統(tǒng)趨向于過高或過低估計不同亮度區(qū)域邊界的現(xiàn)象稱為“馬赫帶”效應;同時對比度指的是人的視覺系統(tǒng)對某個區(qū)域感覺到的亮度除了依賴于它本身的強度,還與背景有關.馬赫帶效應和同時對比度現(xiàn)象表明人所感覺到的亮度并不是強度的簡單函數(shù).4.比較說明像素鄰域、連接、通路以及連通基本概念的聯(lián)系與區(qū)別。(Please compare thefollowing conceptions and their distinction: (1 neighborhood; (2 adjacency; (3 path; (4 connectivity5.設有某圖像子集中p(3,4,q(8,10兩像素點,試分別計算p和q之間的D4, D8, D E距離.(Given pixels p(3,4 and q(8,10, please calculate the following distance: D4, D8 and D E.6.什么是采樣和量化?什么是灰度分辨率與空間分辨率?它們?nèi)绾斡绊憟D像視覺質(zhì)量以及數(shù)據(jù)量大小?(What are the definition of Sampling and Quantization? What are the definition of grayscale resolution and spatial resolution? How Sampling and Quantization process affect the visual quality and date volume of an image?7.試舉出常用的三種圖像灰度映射規(guī)則并繪出相應的映射曲線。(Please give three commongray-level mapping functions and their figure respectively8.為什么一般情況下對離散圖像的直方圖均衡化并不能產(chǎn)生完全平坦的直方圖?(Whydigital image with histogram equalization process cannot obtain fully flat histogram?離散圖像的灰度級數(shù)有限,只有當灰度級數(shù)趨近于無窮大時,直方圖均衡化才能產(chǎn)生完全平坦的直方圖9. 試給出以下直方圖均衡化的步驟及結果 (Please Do histogram equalization on the given histogram 10. 給定如下灰度圖像,根據(jù)下列要求給出對正方形區(qū)域內(nèi)四個象素進行空間濾波增強的結果:設計一個大小為3x3的空間均值濾波器進行圖像平滑;:利用3x3的標準拉普拉斯算子進行圖像銳化;:以3x3的模板進行圖像中值濾波;(Please filter pixels marked with rectangle: (1 using a 3*3 spatial averaging filter to perform image smoothing; (2 using a standard 3*3 Laplacian operator to perform image sharpening; (3 perform 3*3 median filtering 11. 與均值平滑濾波器相比,中值濾波器有何優(yōu)點? 請給出中值濾波實施步驟。(What advantagesdoes median filter have, compared with averaging filter? Please list necessary procedures how to0.5 0.4 0.3 0.1 00.2 (aperform a median filter與均值平滑濾波器相比,中值濾波器能在消除噪聲的同時保留圖象的細節(jié),其實施步驟為:1.將模板在圖中漫游,并將模板中心與圖中某個象素位置重合;2.讀取模板下各對應象素的位置灰度值;3.將這些灰度值從大到小排成列,找出排在中間位置的灰度值并將其賦給對應模板中心位置的象素;12.試簡單敘述圖像特征在空域與頻域表示下的聯(lián)系與區(qū)別。(When image is represented inspatial and frequency domains respectively, what similarity or differences do they have?13.分別畫出低頻增強濾波器, 高頻增強濾波器轉移函數(shù)曲線;(Please draw the transfer functioncurves for low-frequency filter and high-frequency filter respectively.14.將高頻增強和直方圖均衡化結合起來使圖像邊緣銳化是一種常用的圖像增強技術。請問以上兩個操作的先后順序?qū)υ鰪娦Ч杏绊憜?為什么?(In order to sharpen the edge of an image, it is common to use high-frequency emphasis and histogram equalization together. Does the sequence of implementing two technologies have effect on results? Why?15.同態(tài)濾波的理論基礎和依據(jù)是什么?請給出實施步驟。(What is the theory of homomorphicfiltering? Please list the procedures to perform this filter同態(tài)濾波的目的是壓縮圖像整體范圍的同時,擴張用戶所感興趣的細節(jié)特征的灰度級范圍;其理論基礎和依據(jù)是假設光照模型為照度分量與反射分量的乘積,由于照度分量變化緩慢,對應于頻域中高頻成分,而反射分量對應于頻域中低頻成分,故可通過減弱低頻和增強高頻的濾波處理實現(xiàn)上述的目的;16.試簡單敘述圖像增強與圖像復原技術之間的聯(lián)系與區(qū)別。(What are the relationship anddifference between image enhancement and image restoration technology?17.若成像系統(tǒng)為線性移不變系統(tǒng),且僅受加性噪聲n(x,y干擾,即滿足:g(x,y = Hf(x,y + n(x,y, 請給出該系統(tǒng)下的圖像退化模型并從沖激響應出發(fā)予以證明。(Give a linear, position-invariant image system and only additional noise n(x,y is considered, namely, g(x,y=Hf(x,y+n(x,y, Please give the image degradation model and prove it by starting with pulse response.18.試給出估計圖像退化函數(shù)的三種方式并簡單敘述其基本思想。(Please summary threeprincipal ways to estimate the degradation functions in image restoration and descript its theory in brief19.逆濾波的基本原理是什么?試對其應用局限性及解決措施進行說明。(What is the theory ofInverse Filtering? Please give comments on its application limitation and propose some solutions逆濾波本質(zhì)上是在忽略噪聲影響情況下對退化圖像進行濾波,其濾波函數(shù)為原退化系統(tǒng)響應函數(shù)的倒數(shù),故當原退化系統(tǒng)響應函數(shù)取值為零時存在計算上的困難,或當取值較小時,受噪聲的影響大;解決措施:頻率受限,僅對零頻附件的區(qū)域進行處理20.如圖所示,設影像空間變換過程中某像素被映射到失 真影像像素A,B,C,D內(nèi)部點P(a,b,若A,B,C,D點的灰度值分別為G A=36, G B=76, G C=46, G D=66,a=0.7,b=0.6,試分別利用最近鄰插值和雙線性插值方法計算點P的灰度值G P. (As shown in figure, apixel P is mapped within one grid with four pixels. Thegray-levels of four pixels are G A=36, G B=76, G C=46,G D=66,and a=0.7,b=0.6. Please calculate the gray-levelsof pixel P by using (1 nearest neighbor interpolation;(2bilinear interpolation.21.光的3基色指的是哪三種基本顏色?對應的3補色是什么?將一個補色和對應的光基色相混合產(chǎn)生何種顏色? 顏料的3基色指的是哪三種基本顏色?對應的3補色又是什么?將一個補色和對應的顏料基色相混合產(chǎn)生何種顏色? 光的3基色, 3補色與顏料的3基色, 3補色之間有何種關系? (Which are Primary Colors of Light? What are Secondary Colors of Light?What happen if we mix primary color of Light with its Secondary color of Light? Which are Primary Colors of Pigments? What are Secondary Colors of Pigments? What happen if we mix primary color of Pigments with its Secondary color of Pigments?22.試比較說明RGB顏色模型和HSI顏色模型. (Please give comments on RGB and HSI colormodels.23.什么是偽彩色圖像處理?試給出偽彩色圖像處理的兩種常用方式。(What is pseudo-colorimage processing? please give two common methods for pseudo-color image processing 24.什么是數(shù)據(jù)冗余?圖像中的數(shù)據(jù)冗余包含哪三個方面?分別解釋之(What is “dataredundancy”? Which kinds of data redundancies can be found in digital image compression?Please describe them respectively.25.圖像壓縮性能評價常采用的準則有哪些?各有什么特點? (Which are the commonly usedcriteria to evaluate performance of image compression? And what character do the criteria has?26.請給出圖像壓縮模型(解碼/譯碼,并對其不同構件的功能進行解釋. (Please givecomprehensive model on image compression (encoding and decoding and have brief explain on different part of model.27.對下表中的信源符號進行哈夫曼編碼,并給出碼字、平均碼長和編碼效率。(Please use theHuffman coding algorithm to encode the symbols in the table and give its Binary code, average length of the code and the code efficiency. 28.假定白色像素為起始, 試對下列二值序列進行行程編碼:1 0 0 1 1 1 0 0 1 1 1 1 0 0 0 0 1 1(Suppose the first pixel is white, please encode the binary symbols using the run-length coding algorithm29.無損預測編碼的基本思想是什么?為什么對預測誤差進行編碼比直接對原始數(shù)據(jù)進行編碼的效率要高?(What is the theory of lossless predictive coding? Why can we get a higher efficiency when we encode the prediction, compared to the encoding of raw data?無損預測編碼基本思想是不直接對原始數(shù)據(jù)進行量化與編碼,而是利用線性預測技術去除象素間的相關性,對預測值與原始數(shù)據(jù)值之間的差異進行量化與編碼;30.變換編碼的基本思想是什么?正交變換選取的依據(jù)是什么?(What is the theory of“transform coding”? and on what we depend to select the orthogonal transformation?其基本思想是先對圖像進行變換,使得變換域中數(shù)據(jù)間的相關性減小或互不相關,從而減小冗余度,在進行量化與編碼;正交變換編碼具有如下特點:a熵保持. 正交變換不丟失信號,通過傳輸變換系數(shù)來傳送信息;b能量集中. 變換域中的能量集中于少數(shù)變換系數(shù)上,大多數(shù)的系數(shù)數(shù)值都很小,故對能量小的系數(shù)可粗糙量化象素間的或完全忽略;c去相關. 正交變換能夠去除冗余, 變換系數(shù)的相關性為零或較小;31.試借助集合概念從五個方面對圖像分割給出完整的定義。(Please give accurate definition onimage segmentation32.利用Hough變換進行邊緣連接的基本思想是什么? 試給出Hough變換檢測直線段的基本步驟. (What is the theory of “Hough Transformation”? Please describe the steps using Hough Transformation to link discrete edgels into str