Quality Check for Texel Density

inline float4 CalcTexelDensity(float2 uv, float4 Tex_TexelSize)
{
	float2 dx = ddx(uv);
	float2 dy = ddx(uv);
	float texelArea = abs(dx.x * dy.y - dx.y * dy.x);
	float texelDensity = Tex_TexelSize.x *  Tex_TexelSize.y / sqrt(texelArea);
	return texelDensity;
}