simplest adaptive thresholding custom code

Hi all,

I got this far with the adaptive thresholding, Can a professional explain my errors please?

i am trying to do an adaptive thresholding via (Custom For Loop)manual coding!!

I am not sure if this can work! need a break down of what should happen please!!

Thanks in advance!!

function adthres;

[row col]=size(x);

for i=1:1:n

for j=1:n

x = i - n/2;

y = j - n/2;

j(i,j) = exp(-(x*x)/two_sigma_sq);

end

end

end

Answer 1

[KALYAN ACHARJYA]

adaptive thresholding menas, the threshold value is not fixed, its depends on image or input data

In the first view, This code is messed. As you defined j=1:n, here j is scalar, also j(i,j)>> Here j >> representing vector. I didnot find any statement, which relate to calculate the threshold value or replacing vector elements based the threshold.

some_vector(i,j)=exp(-(x*x)/two_sigma_sq);

This statement finding the each element of 2D vector/matrix

[Matpar]

Lol!! thanks for responding @ KALYAN ACHARJYA really appreciate it!!

I know my code is a mess and I am trying to understand what I am doing!

Can you give me an example of what it should be? So in the future I can reference that example and learn progressively!!

A simple for loop calculating the mean and standard deviation is my aim!!

Can you or anyone provide and example of this please? So that I can learn the processes and it's requirements!

Thank you for aacknowledging my digital presence!!

[KALYAN ACHARJYA]

A simple for loop calculating the mean and standard deviation is my aim!!

Lest one objective at a time: Mean

Input data?? Mean of ??

[Matpar]

Ok! I am following your lead i really would like to learn and understand this @KALYAN ACHARJYA! Seeing that my values and understanding is off, you chose! Thank you for responding!

[KALYAN ACHARJYA]

Mean of what?

Requested you to look here Mean

and standard deviation here

Any specific, doubt, let us know?

[Matpar]

Thanks once more @ KALYAN ACHARJYA! I have seen those/your example, that is not my issue. I am having trouble doing it as a for loop! implementing the mean in a for loop as well as the standard deviation. I was hoping you can provide a demonstration of the task in the simplest form so that I can comprehend it. I have been searching online for an example that shows this so that i can go over it on my own, so that it sticks....

Please assist anticipating your response positively!

[KALYAN ACHARJYA]

Thats why I am asking, please provide the input? Mean of what?? Any array?

Pls elaoborate with example (Maths)?

[Matpar]

Thanks for responding @ KALYAN ACHARJYA

can you help me do a for loop for these arrays please?

threshold = 30

Standard Dev x = [2 2 4; 3 1 2; 6 2 3];

utilisng this mean x = [0 1 1; 1 1 2]

[KALYAN ACHARJYA]

Sorry I didnot get the question. Loop is use to do just reapeating task. The question is, loop use to calculate ??

I assumed, you know the basic of loop.

[Matpar]

yes I understand the basic loop but I am trying to understand how to do adaptive threshold via a for loop!! To do this adaptive threshold, does it require calculating the mean as well as standard deviation? I have been reading but some how I am not getting it. I deceided to see this happen as an example so that it would be a little clearer!

Thank for responding and acknowledging me!

[Matpar]

this is normal thresholding, I am not sure how to do the mean calculation in the same code for adaptive thresholding, This where i reach :

function Car = Thresholding(Gcar)

[rows, cols] = size(Gcar);

Car = zeros(rows, cols);

for i = 1:r

for j = 1:c

if Gcar(i,j) > 100

Car(i,j) = 1;

end

end

end

[Image Analyst]

Replace all that with these simple two lines of code:

function Car = Thresholding(Gcar)
Car = Gcar > 100;

No for loops at all needed.

[Matpar]

Hi thanks for responding @ Image Analyst! But i still ould liketo understand it utilisng the for loops!! can you guide me in the right direction please?

I understood the;

function Car = Thresholding(Gcar)
Car = Gcar > 100;

but still would like to solve the adaptive threshold via for loop and thanks in advance for responding and acknowledging my comments and anwers!!

[Matpar]

Hi @ Image Analysis,

Can you help me understand this Error Please?

Error using images.internal.imageDisplayValidateParams>validateCData (line 119)
If input is logical (binary), it must be two-dimensional.

Error in images.internal.imageDisplayValidateParams (line 27)
common_args.CData = validateCData(common_args.CData,image_type);

Error in images.internal.imageDisplayParseInputs (line 78)
common_args = images.internal.imageDisplayValidateParams(common_args);

Error in imshow (line 246)
    images.internal.imageDisplayParseInputs({'Parent','Border','Reduce'},preparsed_varargin{:});