How to scaling down the image resolution to 300 dpi.in matlab for gray scale image

for ecg signal

Answer 1

[Walter Roberson]

Data arrays do not have DPI resolutions.

Image file formats sometimes have headers that indicate suggested DPI.

If you are producing an output image file, see http://www.mathworks.com/help/matlab/ref/print.html#inputarg_resolution or http://www.mathworks.com/help/matlab/ref/imwrite.html#input_argument_namevalue_xresolution (for PNG files) or http://www.mathworks.com/help/matlab/ref/imwrite.html#input_argument_namevalue_resolution (for TIFF files)