多媒体技术III实验指导书(完整版)

安徽工程大学《多媒体技术III》实验指导书专业：计算机科学与技术计算机与信息学院二零一零年11月目录实验一语音编码....................... 错误！未定义书签。

实验二图像点运算. (5)实验三 JPEG静态图像压缩 (29)实验四小波图像压缩 (16)实验五多媒体课件的制作 (16)实验六数字图像差影分析 (18)实验七数字图像的编码 (20)实验八图像的平滑 (24)附录I 数字图像处理实验部分参考源代码 (30)附录II 数字图像处理系统硬件单元及功能说明 (34)附录III C6000基本结构及硬软件安装配置 (36)实验规程一、同学应在实验前仔细阅读实验指导书。

了解实验内容及要求。

并对有关理论部分进行预习，然后进行实验。

二、实验中，要求同学自己在计算机上建立自己的工作目录，并在实验完毕后认真备份自己的程序和实验结果。

不得在其他目录随意建立和删除文件，严禁在系统盘分区删除重要文件。

三、实验中要认真听从实验指导老师的安排，若实验中系统存在问题，随时和实验指导老师取得联系，问清楚指导老师后再行解决，切不可自己随意安装和删除程序。

四、实验完毕后备份好自己的实验程序和实验结果，并在征得指导老师同意后关闭计算机，同学方可离开实验机房。

五、实验过程中不得大声在机房喧哗，扰乱实验秩序。

实验报告每人一份，按每次实验的实验报告要求誊写相关内容，相关实验结果整理成表格和图纸。

报告必须条理清晰，所记录程序必须加注解释。

实验一 语音编码（2学时）一 实验目的掌握语音信号编码原理了解现代通信语音编码方法二．实验设备计算机三．实验原理脉冲编码调制就是把一个时间连续,取值连续的模拟信号变换成时间离散,取值离散的数字信号后在信道中传输.脉冲编码调制就是对模拟信号先抽样,再对样值幅度量化,编码的过程。

图1-1 PCM 原理图 抽样,就是对模拟信号进行周期性扫描,把时间上连续的信号变成时间上离散的信号.该模拟信号经过抽样后还应当包含原信号中所有信息,也就是说能无失真的恢复原模拟信号.它的抽样速率的下限是由抽样定理确定的.在该实验中,抽样速率采用8Kbit/s.量化,就是把经过抽样得到的瞬时值将其幅度离散,即用一组规定的电平,把瞬时抽样值用最接近的电平值来表示. 一个模拟信号经过抽样量化后,得到已量化的脉冲幅度调制信号,它仅为有限个数值.编码,就是用一组二进制码组来表示每一个有固定电平的量化值.然而,实际上量化是在编码过程中同时完成的,故编码过程也称为模/数变换,可记作A/D.PCM 的原理如图1所示.话音信号先经防混叠低通滤波器,进行脉冲抽样,变成8KHz 重复频率的抽样信号(即离散的脉冲调幅PAM 信号),然后将幅度连续的PAM 信号用"四舍五入"办法量化为有限个幅度取值的信号,再经编码后转换成二进制码.对于电话,CCITT 规定抽样率为抽样信号 抽样信号 量化信号t8KHz,每抽样值编8位码,即共有28=256个量化值,因而每话路PCM编码后的标准数码率是64kb/s.为解决均匀量化时小信号量化误差大,音质差的问题,在实际中采用不均匀选取量化间隔的非线性量化方法,即量化特性在小信号时分层密,量化间隔小,而在大信号时分层疏,量化间隔大. 在实际中广泛使用的是两种对数形式的压缩特性:A律和律.A律PCM用于欧洲和我国,律用于北美和日本.四．实验内容及步骤1．打开计算机，安装和启动MATLAB程序；程序组中“work”文件夹中应有待处理的声音文件（TEOTH.MP3）。

2.调入PCM程序，对语音编码处理。

3.对不同声音文件进行调试并分析实验结果。

样本程序：% Removing all variables, functions, and MEX-files from memory, leaving the% workspace empty.clear all% Deleting all figures whose handles are not hidden.close all% Deleting all figures including those with hidden handles.close all hidden% Clearing all input and output from the Command Window display giving us a clean screen.clc% Opening the file 'TEOTH.mp3' in the read access mode.fid = fopen ('TEOTH.mp3','r');% Generating the input signal 'm(t)' by reading the binary data in 16 bit% integer format from the specified file and writing it into a matrix% 'm(t)'.m = fread (fid,'int16');% Defining the count for efficiency.count = 8500;% Calculating maximum value of the input signal 'm(t)'.Mp = max (m)% Setting number of bits in a symbol.bits = 8;% Defining the number of levels of uniform quantization.levels = 2^bits;% Calculating the step size of the quantization.step_size = (2*Mp)/levels% Setting the sampling frequency.% because the audio signal has a maximum frequency of 4K and according to% Nyquist criteria, we get the following sampling frequency.Fs = 8000;% Setting the sampling instant.Ts = 1;% Setting the number of samples to be used.No_Samples = (2*Fs)+Ts;% Define the time vector for the calculations.time = [1:Fs/64];% Calculating the bit rate.bit_rate = 8000*bits;% Quantizing the input signal 'm(t)'.for k = 1:No_Samples,samp_in(k) = m(k*Ts);quant_in(k) = samp_in(k)/step_size;error(k) = (samp_in(k) - quant_in(k))/No_Samples;end% Indicating the sign of the input signal 'm(t)' and calculating the % quantized signal 'quant_out'.signS = sign (m);quant_out = quant_in;for i = 1:count,S(i) = abs (quant_in(i)) + 0.5;quant_out(i) = signS(i)*round(S(i))*step_size;end% Calculating the quantization noise 'Nq'.Nq = ((Mp)^2)/(3*((levels)^2))% Calculating signal to noise ratio 'SNR'.SNR = 1.5*((levels)^2)Gms = log10(SNR)% Plotting the input signal 'm(t)'.%figure;subplot(4,1,1);plot(time,m(time));title('Message Signal');xlabel('Time');ylabel('m(t)');grid on;% Plotting the quantized signal 'quant_in(t)'.%figure;subplot(4,1,2);stem(time,quant_in(time),'r');title('Quantized Speech Signal');xlabel('Time');ylabel('Levels');grid on;% Plotting the PCM signal 's_out(t)'.%figure;subplot(4,1,3);plot(time,quant_out(time));title('PCM Speech Signal');xlabel('Time');ylabel('PC Signal');grid on;% Plotting the error signal 'error(t)'.subplot(4,1,4);plot(time,error(time));title('Error Signal');xlabel('Time');ylabel('Error(t)');grid on;% Removing all variables, functions, and MEX-files from memory, leaving the% workspace empty.clear all正弦波形用A律PCM间接编码c语言代码：#include <iostream>using namespace std;int main(){const int sect = 8; //number of segement.const int startingVol[sect+1] = {0,16,32,64,128,256,512,1024,2048};// the starting value of every segement.const int quanIntvl[sect] = {1,1,2,4,8,16,32,64};//quantity interval of every Segments, 1 equeal to 1/2048.int pcmInd = 0; //pcm code's index.int pcmCode[sect] = {0,0,0,0,0,0,0,0}; // 8 bit of pcm codes.int sampleValue = 1270;int startPoint; //starting point of the segement starting piont //such as startingVol[startPoint] = 16 or 128 etc.int finePoint; //the starting point of inner segement code.int quanValue; // it's used to store the final quantity value.int quanError; //error caused by quantity.//the following four variables is used in geting the segmentCodeint low = 0;int high = sect;int mid;int loopInd1 = 0; //loop index to get segment codeint loopInd2 = 0; //loop index to get inner segment codes//get the first_digit code of polarity(sampleValue > 0) ? (pcmCode[pcmInd++] = 1) : (pcmCode[pcmInd] = 0); sampleValue = abs(sampleValue); //make sure the voltage is positive//get the segment code using modified halve searchwhile(loopInd1 < 3) //only need 3 loops the segmentCode can be got {mid = (low + high)/2;//after 3 loops, sampeValue falls in startingVol[mid] - startingVol[mid] or //in startingVol[mid-1] - startingVol[mid]if(sampleValue < startingVol[mid]){pcmCode[pcmInd++] = 0;high = mid;startPoint = mid - 1 ;}else{pcmCode[pcmInd++] = 1;low = mid;startPoint = mid;}loopInd1++;}//end while//get the last four bits codes of pcmlow = 0;high = 16; //every segment is split into 16 small segments of the same sizewhile(loopInd2 < 4){mid = (low + high)/2;//make the compare progress clear using the following two setences. quanValue = startingVol[startPoint] + mid * quanIntvl[startPoint];cout<<startingVol[startPoint]<<" + "<<quanIntvl[startPoint]<<" * "<<mid<<" = "<<quanValue <<" ? "<<sampleValue<<endl;//make the compare progress clear using the above two setences.if(sampleValue < startingVol[startPoint] + mid * quanIntvl[startPoint]){pcmCode[pcmInd++] = 0;high = mid;finePoint = mid -1;}else{pcmCode[pcmInd++] = 1;low = mid;finePoint = mid;}loopInd2++;}//end whilequanValue = startingVol[startPoint] + finePoint * quanIntvl[startPoint];quanValue += quanIntvl[startPoint] / 2; //final quantity value. quanError = abs( sampleValue - quanValue); // error of quantity.cout<<"Final quantity value is: "<<quanValue<<endl;cout<<"Error of quantity is: "<<quanError<<endl;cout<<"PCM codes are: ";for(int i = 0; i < 8; i++){cout<<pcmCode[i]<<" ";}//end forcout<<endl;return 0;}五．思考题1.PCM编码方法的优缺点。