unity读取灰度图生成等值线图

准备灰度图 grayTest.png，放置于Assets下StreamingAssets文件夹中。

 

在场景中添加RawImage用于显示最后的等值线图。

 

生成等值线的过程，使用Marching squares中Isolines方式。

https://en.wikipedia.org/wiki/Marching_squares

 

首先将顶点数据与阈值比较，对顶点进行标记。根据四个顶点的标记情况，连接各个线段的中点，组成等值线。

 

测试中在texture2d对线段中点进行涂色以显示。

 

脚本如下：

using System.Collections;

using System.Collections.Generic;

using UnityEngine;

using UnityEngine.UI;

//生成等值线图

public class IsoLinesCreate : MonoBehaviour {

    private Texture2D importImage;//输入灰度图

    private Texture grayImage;//加载灰度图

    private Texture2D outputImage;//输出等值线图

    private bool bCreate=false;

    [Tooltip("用作显示输出的等高线图")]

    public RawImage showImage;

    private int tGrayWidth = 0, tGrayHeight = 0;//灰度图的宽和高

    void Start () {

        StartCoroutine(loadImage("grayTest.png", (t) => grayImage = t));

    }

	void Update () {

        if (grayImage!=null)

        {

            if (bCreate==false)

            {

                importImage = (Texture2D)grayImage;

                outputImage = (Texture2D)grayImage;

                tGrayWidth = grayImage.width;

                tGrayHeight = grayImage.height;

                showImage.rectTransform.sizeDelta = new Vector2(tGrayWidth,tGrayHeight);

                //测试不同阈值不同颜色等值线绘制

                trackIsoline(0.5f,Color.blue,2);

                trackIsoline(0.6f, Color.green, 2);

                trackIsoline(0.7f, Color.yellow, 2);

                trackIsoline(0.8f, Color.red, 2);

                showImage.texture = outputImage;

                bCreate = true;

            }

        }

	}

    //加载图片

    IEnumerator loadImage(string imagePath, System.Action<Texture> action)

    {

        WWW www = new WWW("file://" + Application.streamingAssetsPath + "/" + imagePath);

        yield return www;

        if (www.error == null)

        {

            action(www.texture);

        }

    }

    /// <summary>

    /// 等值线追踪

    /// </summary>

    /// <param name="threshold">灰度阈值</param>

    /// <param name="colorP">颜色</param>

    /// <param name="step">步长 为偶数</param>

    private void trackIsoline(float threshold,Color colorP,int step)

    {

        for (int i = 0; i < tGrayWidth-step; i+=step)

        {

            for (int j = 0; j < tGrayHeight-step; j+=step)

            {

                //标记顶点状态

                int tempCount = 0;//0000

                if (importImage.GetPixel(i,j).grayscale>threshold)

                {

                    tempCount += 1;//0001

                }

                if (importImage.GetPixel(i+step, j).grayscale > threshold)

                {

                    tempCount += 8;//1000

                }

                if (importImage.GetPixel(i+step, j+step).grayscale > threshold)

                {

                    tempCount += 4;//0100

                }

                if (importImage.GetPixel(i, j+step).grayscale > threshold)

                {

                    tempCount += 2;//0010

                }

                int t = step / 2;

                //根据顶点标记情况处理中点连线（此处对中点进行上色）

                switch (tempCount)

                {

                    case 0:

                    case 15:

                        break;

                    case 1:

                    case 14:

                        outputImage.SetPixel(i+t,j,colorP);

                        outputImage.SetPixel(i,j+t,colorP);

                        break;

                    case 2:

                    case 13:

                        outputImage.SetPixel(i , j+t, colorP);

                        outputImage.SetPixel(i+t, j + 2*t, colorP);

                        break;

                    case 3:

                    case 12:

                        outputImage.SetPixel(i+t, j, colorP);

                        outputImage.SetPixel(i + t, j + 2 * t, colorP);

                        break;

                    case 4:

                    case 11:

                        outputImage.SetPixel(i +2* t, j+t, colorP);

                        outputImage.SetPixel(i + t, j + 2 * t, colorP);

                        break;

                    case 5:

                        outputImage.SetPixel(i + t, j, colorP);

                        outputImage.SetPixel(i + 2*t, j +  t, colorP);

                        outputImage.SetPixel(i , j + t, colorP);

                        outputImage.SetPixel(i + t, j + 2 * t, colorP);

                        break;

                    case 6:

                    case 9:

                        outputImage.SetPixel(i, j + t, colorP);

                        outputImage.SetPixel(i +2* t, j + t, colorP);

                        break;

                    case 7:

                    case 8:

                        outputImage.SetPixel(i+t, j, colorP);

                        outputImage.SetPixel(i + 2 * t, j + t, colorP);

                        break;

                    case 10:

                        outputImage.SetPixel(i + t, j, colorP);

                        outputImage.SetPixel(i, j + t, colorP);

                        outputImage.SetPixel(i + 2*t, j+t, colorP);

                        outputImage.SetPixel(i + t, j + 2*t, colorP);

                        break;

                }

            }

        }

        outputImage.Apply();

    }

}

本文链接 https://www.cnblogs.com/gucheng/p/10107696.html