Pseudocode

Input:

Color image Q

1. Find indentation mark

Get color channels R, G, B from Q

Find channel A with Maximun entropy

Binarize A, using the proposed method

Fill holes and remove noise using mathematical morphology

Label objects

Select larger object

2. Indentation corner detection:

Using local maximum radius:

Find corners $C_R$

Get Quadrature index $Q_R$

Using indentation perimeter:

Find corners $C_P$

Get Quadrature index $Q_P$

Using Hough transform:

Find corners $C_H$

Get Quadrature index $Q_H$

3. Find best indentation result:

if ($Q_R+0.05$ > $Q_P$ && $Q_R+0.05$ > $Q_H$) {

Select local maximum radius solution }

else if ($Q_P+0.05$ > $Q_H$ && $Q_P+0.05$ > $Q_R$) {

Select Perimeter solution }

else{

Select Hough solution }

4. Calculate hardness estimation HV.

Output: HV