How to detect and highlight the edges of an image in Java

Edge detection can be a difficult feature to implement into a photo app. Today, we will be looking at how to accomplish this without all the headache. In fact, we should be finished in just a few minutes. Let’s get started

First we need to dynamically compile our library using Jitpack. This will require the following references to be added to pom.xml:





Now call filterEdgeDetect, provide an image and effect radius:

// Import classes://import com.cloudmersive.client.invoker.ApiClient;//import com.cloudmersive.client.invoker.ApiException;//import com.cloudmersive.client.invoker.Configuration;//import com.cloudmersive.client.invoker.auth.*;//import com.cloudmersive.client.FilterApi;ApiClient defaultClient = Configuration.getDefaultApiClient();// Configure API key authorization: ApikeyApiKeyAuth Apikey = (ApiKeyAuth) defaultClient.getAuthentication("Apikey");Apikey.setApiKey("YOUR API KEY");// Uncomment the following line to set a prefix for the API key, e.g. "Token" (defaults to null)//Apikey.setApiKeyPrefix("Token");FilterApi apiInstance = new FilterApi();Integer radius = 56; // Integer | Radius in pixels of the edge detection operation; a larger radius will produce a greater effectFile imageFile = new File("/path/to/file"); // File | Image file to perform the operation on.  Common file formats such as PNG, JPEG are supported.try {byte[] result = apiInstance.filterEdgeDetect(radius, imageFile);System.out.println(result);} catch (ApiException e) {System.err.println("Exception when calling FilterApi#filterEdgeDetect");e.printStackTrace();}

And we are done! It’s really that simple. Let’s use this photo to test it out:

Image for post
Image for post

We shall set the radius to 1 and here is what we get:

Image for post
Image for post

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