Compress image with PCM encoder
10 visualizaciones (últimos 30 días)
Mostrar comentarios más antiguos
Marian-Catalin Pirvulescu
el 24 de Feb. de 2020
Respondida: Pujitha Narra
el 26 de Feb. de 2020
For an equation like x(t) = A*sin(2*pi*f*t) the result is code like this:
% Analog signal
f=2; % Maximum freq of the input signal
fs=5*f;
t=0:1/fs:1;
a=2;
x=a*sin(2*pi*f*t);
% Amplitude shifting
x_pos=x+a;
% Quantization
quant=round(x_pos);
% Decimal to binary
encoder=de2bi(quant, 'left-msb');
% Receiver
decoder=bi2de(encoder,'left-msb');
% Shifting the amplitude back
x_out=decoder-a;
My question is, for a given .PGM image, how can I compress it with a PCM encoder following these steps (analog signal- sampler-quantizer-encoder-decoder) and change its bits per pixel?
2 comentarios
Walter Roberson
el 24 de Feb. de 2020
The numeric values read in by imread() can already be considered to be quantized. However if you wanted, you could quantize further. For example, you might do
quant = round(TheImage, -1);
which would round uint8 or uint16 values to the nearest 10.
encoder=de2bi(quant, 'left-msb');
For consistency you should be passing in N, the minimum number of digits to use.
Respuestas (1)
Pujitha Narra
el 26 de Feb. de 2020
Hi,
This is one of the several submissions in MATLAB File Exchange. Feel free to contact the author of this submission directly for specific questions about the implementation.
0 comentarios
Ver también
Categorías
Más información sobre PCM en Help Center y File Exchange.
Productos
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!