How do I load and display an image stored in a separate .mat file?

I am trying to load an image from a provided file and display the image for a class project. We were given the following bit of code to do this so be gentle with me. The prupose of doing this to use linear algebra to do image compression of the data matrix for the image.

image = load("MAT 350 Project Two MATLAB Image.mat");
figure(1);
imshow(image);

And I get the following errors.

Error using imageDisplayValidateParams

Expected input number 1, I, to be one of these types:

double, single, uint8, uint16, uint32, uint64, int8, int16, int32, int64, logical

Instead its type was struct.

Error in images.internal.imageDisplayValidateParams (line 11)

validateattributes(common_args.CData, {'numeric','logical'},...

Error in images.internal.imageDisplayParseInputs (line 79)

common_args = images.internal.imageDisplayValidateParams(common_args);

Error in imshow (line 253)

images.internal.imageDisplayParseInputs({'Parent','Border','Reduce'},preparsed_varargin{:});

Answer 1

[Matt J]

If you look at,

disp(image)

you will see that image is a struct as the error message is telling you. What you probably meant to do is,

image=load("MAT 350 Project Two MATLAB Image.mat").whatever_the_name_of_the_variable_in_the_file_is

[Nicholas]

I wish that was in the documentation for the load function. I was trying...

image = load(file, variable) and using "A" for the variable as in the current function documentation.

Thanks!

[Matt J]

image = load(file, variable) and using "A" for the variable as in the current function documentation.

The documentation does not offer that as a way to avoid A being wrapped in a struct. Perhaps you saw,

>> load(file, variable)

without an output argument from load(). That syntax would have worked as well, but is not recommended by the user community.

[Walter Roberson]

variable = load(file)

is defined in the documentation. If file is a .mat file then the output is a struct array with one field for each variable in the .mat file. If file is a text file, then the output is a 2D numeric array.

[Stephen23]

"I wish that was in the documentation for the load function."

Source: https://www.mathworks.com/help/matlab/ref/load.html#description