CODEWITHSUNDEEP
matlabprintingexportresolutionaxes
Llouis
Llouis

Reputation: 56

Export image at full resolution with axes in MATLAB

I am trying to save a large image (1641x6139) at full resolution with MATLAB with axes. Doing this without axes is easy using the imwrite command. To plot the image with axes, I write:

image(x,y,my_image);

Because the image is very large, MATLAB automatically reduces the resolution of the image. The window size would have to be significantly larger than the screen to display the entire image at full resolution. I have tried a couple different approaches to exporting the figure and each runs into the same problem: the image is pixelated at a coarser resolution than the original image. The problem is not that the new image has fewer pixels; instead, neighboring pixels have been assigned the same value, creating the appearance of coarser-scale pixelation.

For example, where H is the figure handle, I tried:

set(H, 'PaperPosition', [0, 0, width , height ])
print -dpng -r500 my_filename

Increasing width, height, or resolution all had the effect of increasing the number of pixels in the image, but the apparent pixelation is unchanged.

I also tried using the function export_fig, which seems to be designed for this type of problem, claiming to export figures with contained images in their native resolution. The resulting image appears to have the correct number of pixels, but as before the problem is that neighboring pixels have the same value, creating the appearance of coarser pixelation absent from the original image. The code I used is:

export_fig(my_filename,'-a1','-native')

Here are a couple images showing roughly the same zoomed in portion of my image:

zoomed in images (original and using export_fig)

The first is the original image and the second is the image resulting from export_fig. The second looks pixelated, although again note that each image contains roughly the same number of actual pixels.

Any advice/solutions would be much appreciated! This problem has been much more frustrating than I expected.

Upvotes: 1

Views: 477

Answers (1)

Llouis
Llouis

Reputation: 56

I figured out a simple solution. First, I create a blank image of the correct size, add the axes, and then use export_fig to generate an image of the axes. Then, I write my full-resolution image into the image matrix, and save the resulting image using imwrite.

Upvotes: 1

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