ThermalBlit.cs

using System.Collections;
using UnityEngine;

[ExecuteInEditMode]
public class ThermalBlit : MonoBehaviour
{
    [SerializeField]
    private Material material;

    public void Start()
    {
        Camera.main.depthTextureMode = DepthTextureMode.DepthNormals;// depthnormals are needed for outline effect
    }

    // Postprocess the image
    void OnRenderImage(RenderTexture source, RenderTexture destination)
    {
        Graphics.Blit(source, destination, material);
    }
}