回上一畫面
課程名稱:數位信號處理
第二次小考
問答題 100 %
閉書考 共8題 請用答案紙作答
- 試繪圖說明選頻濾波器之分類為何?
2. 類比的 IIR 低通濾波器有四種基本的 IIR 濾波器:
(1)巴特渥斯濾波器 (Butterworth filter)
(2)柴比雪夫第一型濾波器(Chebysher filter)
(3)柴比雪夫第二型濾波器 (chebysher II filter)
(4)橢圓濾波器 (elliptiz function filter)
試繪圖說明之。
3. 有一 matlab 程式如下:
[n,Wn]=buttord(0.1,0.4,1,15)
﹐Wn 是利用雙線性轉換將頻率軸作非線性壓縮的結果。假設在未上機前,請試以自行計算的方式粗略算出其結果。
Ans: n = 2
Wn = 0.1907
- (a)何謂鍊碼 (Chain Code)? 試繪圖說明之。
(b) 何謂半色階處理法( half-tone) ?
- 何謂振顫法 (dithering) ?
5. 有一二值影像如下:
|
0
|
1
|
0
|
0
|
0
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
0
|
|
1
|
0
|
1
|
1
|
0
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
0
|
|
1
|
0
|
1
|
1
|
1
|
1
|
1
|
0
|
|
0
|
0
|
0
|
0
|
1
|
1
|
1
|
0
|
|
1
|
0
|
0
|
0
|
1
|
0
|
1
|
1
|
|
0
|
0
|
0
|
0
|
1
|
1
|
1
|
1
|
(1) 試求此二值影像開啟運算之結果
- 試求此二值影像關閉運算之結果
- 試求此二值影像去除擴張點 (delete the dilated point) 之結果
- 試求此二值影像去除孤立點 (delete the isolated point) 之結果
- 試求此二值影像補回遺漏點 ( recover the missing point) 之結果
Ans:
(1)
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
0
|
0
|
0
|
0
|
0
|
0
|
1
|
1
|
|
0
|
0
|
0
|
0
|
0
|
0
|
1
|
1
|
(2)
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
|
1
|
0
|
0
|
0
|
1
|
1
|
1
|
1
|
|
1
|
0
|
0
|
0
|
1
|
0
|
1
|
1
|
|
1
|
0
|
0
|
0
|
1
|
1
|
1
|
1
|
(3)
|
0
|
1
|
0
|
0
|
0
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
0
|
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
0
|
|
1
|
0
|
1
|
1
|
1
|
1
|
1
|
0
|
|
0
|
0
|
0
|
0
|
1
|
1
|
1
|
0
|
|
1
|
0
|
0
|
0
|
1
|
0
|
1
|
1
|
|
0
|
0
|
0
|
0
|
1
|
1
|
1
|
1
|
(4)
|
0
|
1
|
0
|
0
|
0
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
0
|
|
1
|
0
|
1
|
1
|
0
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
0
|
|
1
|
0
|
1
|
1
|
1
|
1
|
1
|
0
|
|
0
|
0
|
0
|
0
|
1
|
1
|
1
|
0
|
|
1
|
0
|
0
|
0
|
1
|
0
|
1
|
1
|
|
0
|
0
|
0
|
0
|
1
|
1
|
1
|
1
|
(5)
|
0
|
1
|
0
|
0
|
0
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
0
|
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
1
|
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
0
|
|
1
|
0
|
1
|
1
|
1
|
1
|
1
|
0
|
|
0
|
0
|
0
|
0
|
1
|
1
|
1
|
0
|
|
1
|
0
|
0
|
0
|
1
|
0
|
1
|
1
|
|
0
|
0
|
0
|
0
|
1
|
1
|
1
|
1
|
- 在影像分割之後,影像中的物体已經被獨立出來,這時候我們可以對物体的幾何特性加以分析計算,所計算的項目包括哪些?
- (a)試求序列x(n)= u [n] 之Z-轉換及其ROC ?
- 試求 z > 0.5之反Z-轉換?
Ans: (a)X(z)=z/(z-0.3) R.O.C.: |z|>.3
(b)x(n)=0.5nu[n]
8.信號之 Z- 轉換 X(Z) 、數位濾波器之 Z- 轉換 H(Z) 及其濾波後輸出之 Z- 轉換 Y(Z) 三者之之關係可表示如下:
在此 b(i)=b(1),b(2),...,b(nb+1)及a(i)=a(2),...,a(na+1) 皆為濾波器之係數,而 na,nb 為濾波器之階數。試就 na 及 nb 等於或大於零來討論濾波器之屬性。