canny边缘提取matlab代码

Canny边缘检测是一种广泛应用的图像处理技术，它由John Canny于1986年提出，用于检测图像中的强边缘。在MATLAB中，可以使用内建函数`imfilter`和`edge`来进行Canny边缘检测。以下是一个简单的Canny边缘检测的MATLAB代码示例：

function edges = canny(image)
% Step 1: Convert to grayscale if necessary
if iscolor(image)
    image = rgb2gray(image);
end

% Step 2: Gaussian blur for noise reduction
sigma = sqrt(2); % standard deviation for Gaussian kernel
blurred = imgaussfilt(image, sigma);

% Step 3: Compute gradient magnitude and direction
[Gx, Gy] = imgradient(blurred, 'sobel'); % Sobel operator for gradient calculation
mag = sqrt(Gx.^2 + Gy.^2); % Gradient magnitude
theta = atan2(Gy, Gx); % Gradient orientation in radians

% Step 4: Non-max suppression
[mag_filtered, theta_filtered] = nonmaxsuppression(mag, theta);

% Step 5: Double thresholding
low_threshold = 0.1 * max(max(mag_filtered));
high_threshold = low_threshold * 2;
edges = mag_filtered > high_threshold & (mag_filtered >= low_threshold | ispropagate(theta_filtered));

% Step 6: Edge tracing (optional)
% edges = edge(edges, 'canny');
end

% Function to perform non-max suppression
function [output_mag, output_theta] = nonmaxsuppression(input_mag, input_theta)
% ... (implementation details omitted due to brevity)

注意，这个例子省略了非极大值抑制（Non-Maximum Suppression）和边缘跟踪的部分，因为它们比较复杂，但对于理解Canny算法的关键步骤已经足够。如果你需要完整的代码，可以参考MATLAB官方文档或在线教程。