Compress image with PCM encoder
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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 Comments
Walter Roberson
on 24 Feb 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.
Answers (1)
Pujitha Narra
on 26 Feb 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.
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