#CustomVision – Sort and manage Json response estimation in a single line of code

Hi!

On my Custom Vision samples, I usually send an image to a CustomVision.ai HTTP Endpoint, and I process the Json result. The results are very easy to understand, however, I created a C# converter class to help with the Custom Vision results.

To create this class I navigate: http://json2csharp.com/, and paste a sample result and make some changes on the result. The output and useful class is this one:

	using System;
	using System.Collections.Generic;
	using System.Globalization;
	using Newtonsoft.Json;
	using Newtonsoft.Json.Converters;
	// created with https://app.quicktype.io/#l=cs&r=
	namespace DistractedDriverDetectionShared
	{
	public partial class CustomVisionEstimation
	{
	[JsonProperty("created")]
	public DateTimeOffset Created { get; set; }
	[JsonProperty("id")]
	public string Id { get; set; }
	[JsonProperty("iteration")]
	public string Iteration { get; set; }
	[JsonProperty("predictions")]
	public Prediction[] Predictions { get; set; }
	[JsonProperty("project")]
	public string Project { get; set; }
	}
	public partial class Prediction
	{
	[JsonProperty("boundingBox")]
	public object BoundingBox { get; set; }
	[JsonProperty("probability")]
	public double Probability { get; set; }
	[JsonProperty("tagId")]
	public string TagId { get; set; }
	[JsonProperty("tagName")]
	public string TagName { get; set; }
	}
	public partial class CustomVisionEstimation
	{
	public static CustomVisionEstimation FromJson(string json) => JsonConvert.DeserializeObject<CustomVisionEstimation>(json, Converter.Settings);
	}
	public static class Serialize
	{
	public static string ToJson(this CustomVisionEstimation self) => JsonConvert.SerializeObject(self, Converter.Settings);
	}
	internal static class Converter
	{
	public static readonly JsonSerializerSettings Settings = new JsonSerializerSettings
	{
	MetadataPropertyHandling = MetadataPropertyHandling.Ignore,
	DateParseHandling = DateParseHandling.None,
	Converters =
	{
	new IsoDateTimeConverter { DateTimeStyles = DateTimeStyles.AssumeUniversal }
	},
	};
	}
	}

view raw CustomVisionEstimation.cs hosted with ❤ by GitHub

It’s a very simple class, and the best way to describe it, is to show an usage scenario

	// open file as byte array
	var byteData = GetImageAsByteArray(imageFilePath);
	// prediction
	var client = new HttpClient();
	using var content = new ByteArrayContent(byteData);
	content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
	var response = await client.PostAsync(Url, content);
	var jsonResponse = await response.Content.ReadAsStringAsync();
	// Display results
	var est = CustomVisionEstimation.FromJson(jsonResponse);
	var prediction = est.Predictions.OrderByDescending(x => x.Probability).FirstOrDefault();
	Console.WriteLine(@$"{prediction.TagName} – {prediction.Probability}");

view raw CustomVisionEstimationSampleUsage.cs hosted with ❤ by GitHub

The main remarks points are

• Lines 1 to 9, open a local file, create a HTTP client and make the HTTP Post request
• Line 12, convert the json response (string) to a C# object and then get the best prediction
• Where the best prediction is a single Linq code sorting the predictions by probability and selecting the 1t one.

Easy and amazing!

Happy Coding!

Greetings @ Burlington

El Bruno

References

• Custom Vision, CustomVision.ai
• Json2CSharp, http://json2csharp.com/