Creating .PNG image from temperature values

The size of my table (i.e. variables) is 462x622 double

I used the code below to create an image:

imagesc(image); colormap jet; axis off

However, the pixel size of the resulting image is 420x560.

How can I make an image with the same pixel size as the variables?

Answer 1

[Ameer Hamza]

I guess you are using saveas() or some other function to save the .png file. They are not suitable for maintaining the resolution. Use imwrite() as shows in the following lines

image = round(rescale(image, 1, 256));
imwrite(image, jet, 'image.png');

[Oliver Ramos]

Thank you! this exactly solved my problem.

[Ameer Hamza]

I am glad to be of help!!!

[Oliver Ramos]

sorry, I want to understand, can you please explain what does round function and rescale(image, 1, 256) do in the image?

[Ameer Hamza]

jet colormap have 256 colors. The line

image = round(rescale(image, 1, 256));

converts the image into an indexed image. Read about indexed image here: https://www.mathworks.com/help/images/image-types-in-the-toolbox.html#f14-17587

[Oliver Ramos]

Thank you very much!!

[Ameer Hamza]

I am glad to be of help!