Why i get this error

Undefined operator '&' for input arguments of type 'matlab.graphics.primitive.Image'. why i am getting this error. i have to multiply 2 binary images pixel by pixel in matlab. groungtruth and output are two binary images. both are same but are segmented with two different techniques.

function r=eval_metrics(output,groundtruth)

TP_image=groundtruth&output;

TP=sum(TP_image(:));% # of hits (True Positive)

FN_image=groundtruth&~output;

[Image Analyst]

Before the error, put this:

whos output
whos groundtruth

What do you see in the command window? How did you actually get the image that is not a logical array but is actually of type 'matlab.graphics.primitive.Image'?

Is this the same as https://www.mathworks.com/matlabcentral/answers/702337-why-i-get-this-error?s_tid=srchtitle

where we're not sure if you've accepted an answer or not and never attached your image so people can run your code. If so, then why? If not, what's the difference?

[Rik]

Not really the Christmass spirit, to edit away your question. I restored it from the Google cache.

Answer 1

[Steven Lord]

Generally you're going to want to perform arithmetic and/or logical operations on the image data not the image graphics object.

im = imread('eight.tif');
h = imagesc(im);

whos im h

  Name        Size             Bytes  Class                              Attributes

  h           1x1                  8  matlab.graphics.primitive.Image              
  im        242x308            74536  uint8                                        

Arithmetic and logical operations are defined on variables of class uint8 but not on variables of class matlab.graphics.primitive.Image.

im(1, 1) & im(1, 2) % works

ans = logical
   1

h(1, 1) & true % does not work

Operator '&' is not supported for operands of type 'matlab.graphics.primitive.Image'.

[Walter Roberson]

Though if I recall correctly you can

h(1, 1) ~= 0 & true

[Walter Roberson]

one of your two inputs is not a matrix of data, and is instead the handle to an image() or imshow() or imagesc() when it should not be. We would need to see the code you are calling the function with

[Syeda Noor]

Can you give me your email, so i can share my files with you.

[Steven Lord]

Using the variables in my example, don't try to perform arithmetic or logical operations on h, the output of a call to image or imagesc. Instead perform arithmetic or logical operations on im, the raw data.

[Walter Roberson]

I suspect that you did

out = imshow(array > Threshold)

and assumed that the output would be the image array resulting from the comparison. The output of imshow is the handle to a graphic object.

[Walter Roberson]

output = imshow(imcomplement(y));

As I said, the output of imshow is a graphics handle, not the array of data. Save the result of imcomplement to output and imshow(output)

[Steven Lord]

As Walter said, replace:

output = imshow(imcomplement(y));
eval_metrics(output,groundtruth);

with something like:

C = imcomplement(y);
output = imshow(C);
eval_metrics(C,groundtruth);

[Syeda Noor]

Yes it works.

[Syeda Noor]

Can you please help me, how to make a binary mask of circular colored image. Which i have to apply on that image for segmentation.

[KALYAN ACHARJYA]

From the Original Image or any other means?

[Walter Roberson]

Try imbinarize()

[Syeda Noor]

Yes from original color image. Image is in round shape

[Walter Roberson]

You have not posted a sample image.