Application of Histogram Equalization for Image Enhancement in Corrosion Areas

Table 4

Standard deviation of each image before and after enhancement.

Enhanced method	Corrosion image 1	Corrosion image 2	Corrosion image 3
Original image	42.5062	44.4076	43.7615
Dark detail enhancement [24]	48.7652	47.6215	49.7351
Defogging algorithm [17]	52.3517	53.8714	52.9013
Homomorphic filtering [15]	55.5426	56.0918	57.8872
Histogram [26]	60.5412	62.7615	61.0195
Proposed algorithm	63.3812	65.3911	64.3075