Kristin, try this. Again, no idea what you want to measure but I'm pretty sure Sobel is not the best approach. Why do you think it is?
% Demo by Image Analyst
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
clear; % Erase all existing variables. Or clearvars if you want.
workspace; % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;
markerSize = 40;
%--------------------------------------------------------------------------------------------------------
% READ IN IMAGE
fileName = 'drosophila_embryo_wild_type.jpg';
grayImage = imread(fileName);
% Get the dimensions of the image.
% numberOfColorChannels should be = 1 for a gray scale image, and 3 for an RGB color image.
[rows, columns, numberOfColorChannels] = size(grayImage)
if numberOfColorChannels > 1
% It's not really gray scale like we expected - it's color.
% Extract the blue channel (so the magenta lines will be white).
grayImage = grayImage(:, :, 3);
end
%"sobelpic" is the name of the image.
%I'm getting an error that my subplot is too large.
%I'm thinking that I need to manipulate my threshs (somehow?) because ultimately I need to choose "0.34" as a threshold value according to my professor.
threshs = linspace(0.01, 0.8, 9);
%--------------------------------------------------------------------------------------------------------
% Display the image.
subplot(4, 3, 1);
imshow(grayImage, []);
impixelinfo;
axis('on', 'image');
title('Original Image', 'FontSize', fontSize, 'Interpreter', 'None');
hold on
drawnow;
% Maximize window.
g = gcf;
g.WindowState = 'maximized'
drawnow;
% Get a sobel image.
sobelPic = imgradient(grayImage,"sobel");
subplot(4, 3, 2);
imshow(sobelPic, []);
impixelinfo;
axis('on', 'image');
title('Sobel Image', 'FontSize', fontSize, 'Interpreter', 'None');
hold on
drawnow;
subplot(4, 3, 3);
histogram(sobelPic);
grid on;
xlim([0, 150]);
title('Histogram of Sobel Image', 'FontSize', fontSize, 'Interpreter', 'None');
%--------------------------------------------------------------------------------------------------------
% Compute binary image
for k =1:length(threshs)
t = threshs(k);
BW = im2bw(sobelPic,t);
subplot(4, 3, k+3);
imshow(BW, []);
caption = sprintf('Thresholed at %.2f', t);
title(caption);
drawnow;
end
