HawkeyeVision/Hawkeye.VisionBuilder.Workflow/Operations/Simple/Blobs/FindBlobOperation.cs

using Hawkeye.VisionBuilder.Workflow.Datatypes.Elements.Origin;
using Hawkeye.VisionBuilder.Workflow.Datatypes.Elements.Poly;
using Hawkeye.VisionBuilder.Workflow.Links;
using Hawkeye.VisionBuilder.Workflow.Operations.Attributes;

using OpenCvSharp;
using Point = OpenCvSharp.Point;
using RectangleElement = Hawkeye.VisionBuilder.Workflow.Datatypes.Elements.Rectangle.RectangleElement;

namespace Hawkeye.VisionBuilder.Workflow.Operations;

[Category("Simple/Blobs")]
public class FindBlobOperation : BaseOperation, IHaveOrigin, IHaveSearchArea
{
    private readonly WorkflowList _workflowList;

    public int MinArea { get; set; } = 100;

    public int MaxArea { get; set; } = 99999;

    public int MinRadius { get; set; } = 0;

    public int MaxRadius { get; set; } = 99999;

    public bool BadIfFound { get; set; }



    public Guid ReferenceId { get; set; } = new Guid();

    public RectangleElement SearchArea { get; set; }

    //processing result of current element
    [NotForTool] public OriginElement Origin { get; private set; } = OriginElement.Default;

    public FindBlobOperation(WorkflowList workflowList)
    {
        _workflowList = workflowList;
        SearchArea = new RectangleElement()
        {
            Editable = true,
            Location = Vector2.One * 100,
            Size = Vector2.One * 100,
            IsGood = true
        };
    }


    protected override void InterpretInternal(Context context)
    {
        if (!CheckImageExists(context)) return;
        if (!CheckGrayscale(context)) return;

        SearchArea.MovePivot(_workflowList.GetOriginById(ReferenceId).Origin.Location);

        var img = context.ActiveImage.ImageData;
        var mat = new Mat(img.Size(), img.Type(), Scalar.Black);

        SearchArea.FillMat(mat);

        var contoursMat = img.BitwiseAnd(mat).ToMat();


        var contours = contoursMat.Threshold(128, 255, ThresholdTypes.Binary)
            .FindContoursAsArray(RetrievalModes.List, ContourApproximationModes.ApproxSimple);

        //case: no blobs found
        if (contours.Length == 0)
        {
            Status = "No blobs found";
            SearchArea.IsGood = false;
            context.GraphicsElements.Add(SearchArea);
            Result = BadIfFound;
            return;
        }

        int GetContourRadius(Point[] contour)
        {
            Cv2.MinEnclosingCircle(contour, out var center, out var radius);
            return (int)radius;
        }
        //case: blobs found but not matching criteria
        var contour = contours.Select(x => new { c = x, area = (int)Cv2.ContourArea(x),radius= GetContourRadius(x) })
            .OrderBy(x => Math.Min(Math.Abs(x.area - MinArea), Math.Abs(x.area - MaxArea)));
        var match = contour.Where(x=>x.c.Length>1)
            .Where(x => x.area >= MinArea && x.area <= MaxArea)
            .FirstOrDefault(x => x.radius >= MinRadius && x.radius <= MaxRadius);

        if (match == null)
        {
            var best = contour.First();
            
            Status = $"Area: {best.area} Radius: {best.radius}";
            PolyElement poly = new PolyElement() { IsGood = BadIfFound };

            poly.Points = best.c.Select(x => new Vector2(x.X, x.Y)).ToArray();

            context.GraphicsElements.Add(poly);

            
            context.GraphicsElements.Add(SearchArea);
            Result = BadIfFound;
            return;
        }

        {
            PolyElement poly = new PolyElement() { IsGood = !BadIfFound };

            poly.Points = match.c.Select(x => new Vector2(x.X, x.Y)).ToArray();

            context.GraphicsElements.Add(poly);
            SearchArea.IsGood = true;
            context.GraphicsElements.Add(SearchArea);
            var center = poly.Points.Aggregate((v1, v2) => v1 + v2) / poly.Points.Length;
            Origin = new OriginElement() { Location = center };
            Status = $"Area: {match.area} Radius: {match.radius}";
            Result = !BadIfFound;
        }
    }

    public override void SetParameters(Dictionary<string, object> parameters)
    {
        base.SetParameters(parameters);

        SearchArea.SetPivot(_workflowList.GetOriginById(ReferenceId).Origin.Location);
    }


    public override void Save(BinaryWriter bw)
    {
        bw.Write(Id.ToString());
        bw.Write(Label);
        bw.Write(MinArea);
        bw.Write(MaxArea);
        bw.Write(MinRadius);
        bw.Write(MaxRadius);
        bw.Write(BadIfFound);
        bw.Write(ReferenceId.ToString());
        
        SearchArea.Save(bw);


    }

    public override void Load(BinaryReader br)
    {
        Id = new Guid(br.ReadString());
        Label = br.ReadString();
        MinArea = br.ReadInt32();
        MaxArea = br.ReadInt32();
        MinRadius = br.ReadInt32();
        MaxRadius = br.ReadInt32();
        BadIfFound = br.ReadBoolean();
        ReferenceId = new Guid(br.ReadString());

        SearchArea.Load(br);
    }
}