I am using the inbuilt MATLAB code for a vector, can anyone please tell me how to use the same code for images?

code is at http://in.mathworks.com/help/comm/ug/source-coding.html#fp6485
predictor = [0 1]; % y(k)=x(k-1)
partition = [-1:.1:.9];
codebook = [-1:.1:1];
t = [0:pi/50:2*pi];
x = sawtooth(3*t); % Original signal
% Quantize x using DPCM.
encodedx = dpcmenco(x,codebook,partition,predictor);
% Try to recover x from the modulated signal.
decodedx = dpcmdeco(encodedx,codebook,predictor);
plot(t,x,t,decodedx,'--')
legend('Original signal','Decoded signal','Location','NorthOutside');
distor = sum((x-decodedx).^2)/length(x) % Mean square error

this code is used for a saw tooth wave , if i want to apply the same on any image...then changes should be in?

[B.k Sumedha]

What are u trying to achieve through that image?

[tina jain]

DPCM is basically a lossless image compression algorithm... I will use it to calculate compression ratio and PSNR.

Answer 1

[Walter Roberson]

Replace

t = [0:pi/50:2*pi];
x = sawtooth(3*t); % Original signal

with

x = YourImage(:);
t = linspace(1, 2*Pi, length(x));

where YourImage is the name of the variable that holds your RGB image.