shader : chroma + edge thin?

Hi...

I use this shader for the chroma

 Shader "Chromakey/Mask" {
 
 
     Properties {
 
         _MainTex ("Base (RGB)", 2D) = "white" {}
         _Transparency ("Transparency", Range (0,1.0)) = 0
     }
 
     SubShader {
 
         ZWrite Off
         Blend SrcAlpha OneMinusSrcAlpha 
         CGINCLUDE
         #include "UnityCG.cginc"
         ENDCG
 
         Pass 
         {
             Lighting Off
             //Cull Off ZWrite On Lighting Off Fog { Mode off } 
             //Blend SrcAlpha OneMinusSrcAlpha
             CGPROGRAM
                 #pragma vertex vert_img
                 #pragma fragment frag
                 #pragma fragmentoption ARB_precision_hint_fastest
                 
                 #pragma target 3.0
                 
                 uniform sampler2D _MainTex;
                 uniform float     _Transparency;
                 
                 half4 frag (v2f_img i) : COLOR 
                 {
                       half4 col = tex2D(_MainTex, i.uv);
                       half4 final = ((col.g - (col.r + col.b)) > _Transparency ) ? half4(col.rgb,0.0) : half4(col.rgb,1.0);
                            
                     return final;
                 }
             ENDCG
         }  
     }
 
     Fallback off
 }
 
 

• my example to remove the green screen behind the man .

I want to add a new 2 options :

1- after the green screen is gone , make as in after effects "Edge Thin"

2- draw outline over the man.

thank you ...