# How to find minimum and maximum pixel value in image

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Med Future on 19 Mar 2022
Commented: Med Future on 21 Mar 2022
Hello Everyone, i hope you are doing well.
I have the following to images. i want detect the pattern and find the minimum and maximum value for the pattern
for example the first image sinewave. i want to detect the shape and find the value for upper peak and lower peak.
same for the second image
Can anybody help me in that
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Med Future on 20 Mar 2022
@Image Analyst Can you please check this

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### Answers (1)

Atsushi Ueno on 19 Mar 2022
Edited: Atsushi Ueno on 20 Mar 2022
>i want detect the pattern and find the minimum and maximum value for the pattern
The images have black background with value 0 and a white line with value 255.
You can use max(org:find) function to find non-zero value in each columns in the picture data.
image = imread('im_003002.png');
[~, wave] = max(image); % thx @Scott MacKenzie for x = 1:size(image,2) wave(x) = find(image(:,x)); end
max(wave) % It is y coordinate value of each dots on the white line.
ans = 991
min(wave) % It is y coordinate value of each dots on the white line.
ans = 981
plot(wave);
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Med Future on 21 Mar 2022
@Atsushi Ueno@_ @Scott MacKenzie @DGM Thank for you answer. First step to find minimum and maximum of the value which is done using above code.
I also want to detect shape for example in periodic waveform im_003002.png the cycle repeat 6 times , i want to detect if any image comes how many cycles are there in the waveform

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