I am preparing image files to be included in a latex document. The image file is generated by printing a Matlab plot.
If I print the plot in eps format, the content of the eps file is fully occupied with the plot;
if I print the plot in pdf format, then there are big margins above and below the plot in the pdf file;
if I use ps2pdf to convert the eps file into a pdf file, the big margins will be added above the plot.
I would like to use pdflatex, so I prefer pdf format of image files. I was wondering how I can save the plot in pdf format without the big margin above and below the plot?
export_fig results (picture size is the same) is: 
