ECE 306L Lab 4 MATLAB Files

part1.m

clear variables
y = imread('moon.tif'); % Target Image File
z = double(y);
maximum = max(z(:));
minimum = min(z(:));
b = 7; % Quantiz Bits
N = 2^b;
Delta = (maximum - minimum)/(N-1);
ztemp = z - minimum;
ztemp = round(ztemp/Delta);
ztemp = ztemp.*Delta + minimum;
fig = image(ztemp);
colormap(gray(256));
axis('image');

part2.m

clear variables
audio = audioread('music.au');
maximum = max(audio(:));
minimum = min(audio(:));
b = 7; % Some bits per px. Modify this.
N = 2^b;
Delta = (maximum - minimum)/(N-1);
codebook_a = minimum-Delta:Delta:maximum;
codebook_b = minimum-(Delta/2):Delta:maximum+(Delta/2);
partition = minimum:Delta:maximum;
[index_a, quantz_a] = quantiz(audio, partition, codebook_a);
[index_b, quantz_b] = quantiz(audio, partition, codebook_b);
q_a_e = transpose(quantz_a) - audio;
q_b_e = transpose(quantz_b) - audio;
figure('name',strcat(int2str(b), ' bits'),'pos',[10 10 500 900])
subplot(4,2,1)
plot(quantz_a)
title('Quantized Audio A')
subplot(4,2,2)
plot(quantz_b)
title('Quantized Audio B')
subplot(4,2,3)
hist(q_a_e, 20);
title('Quantize Error A')
subplot(4,2,4)
hist(q_b_e, 20);
title('Quantize Error B')
[c_a,lags_a] = xcorr(q_a_e,audio,200,'unbiased');
[c_b,lags_b] = xcorr(q_b_e,audio,200,'unbiased');
[ca_a,lagsa_a] = xcorr(q_a_e,200,'unbiased');
[ca_b,lagsa_b] = xcorr(q_b_e,200,'unbiased');
subplot(4,2,5)
plot(lagsa_a,ca_a);
title('Auto-Correlation A')
subplot(4,2,6)
plot(lagsa_b,ca_b);
title('Auto-Correlation B')
subplot(4,2,7)
plot(lags_a,c_a);
title('Cross-Correlation A')
subplot(4,2,8)
plot(lags_b,c_b);
title('Cross-Correlation B')
[sz, ~] = size(q_a_e);
Pa = 1/sz * sum(q_a_e.^2);
Pb = 1/sz * sum(q_b_e.^2);
Po = 1/sz * sum(audio.^2);
PSNRa = Po/Pa;
PSNRb = Po/Pb;
Dista = 1/PSNRa;
Distb = 1/PSNRb;

part4.m

clear variables
audio = audioread('music.au');
maximum = max(audio(:));
minimum = min(audio(:));
Dista = zeros(1,7);
Distb = zeros(1,7);
PSNRa = zeros(1,7);
PSNRb = zeros(1,7);
r = 1:1:7;
for b = 1:1:7
    N = 2^b;
    Delta = (maximum - minimum)/(N-1);
    codebook_a = minimum-Delta:Delta:maximum;
    codebook_b = minimum-(Delta/2):Delta:maximum+(Delta/2);
    partition = minimum:Delta:maximum;
    [index_a, quantz_a] = quantiz(audio, partition, codebook_a);
    [index_b, quantz_b] = quantiz(audio, partition, codebook_b);
    q_a_e = transpose(quantz_a) - audio;
    q_b_e = transpose(quantz_b) - audio;
    [sz, ~] = size(q_a_e);
    Pa = 1/sz * sum(q_a_e.^2);
    Pb = 1/sz * sum(q_b_e.^2);
    Po = 1/sz * sum(audio.^2);
    PSNRa(b) = Po/Pa;
    PSNRb(b) = Po/Pb;
    Dista(b) = 1/PSNRa(b);
    Distb(b) = 1/PSNRb(b);
end
subplot(2,2,1)
plot(r, PSNRa);
title('PSNR A');
xlabel('Bits');
ylabel('PSNR');
subplot(2,2,2)
plot(r, PSNRb);
title('PSNR B')
xlabel('Bits');
ylabel('PSNR');
subplot(2,2,3)
plot(r, Dista);
title('Distortion A')
xlabel('Bits');
ylabel('Distortion');
subplot(2,2,4)
plot(r, Distb);
title('Distortion B')
xlabel('Bits');
ylabel('Distortion');