Measuring of the length of aggregate

Continuing the discussion from Auto measuring fiber length? 1000+ measurements?:

Dear the kinds people in here,

Can all of you to help me how to measure the length of this aggregate?because when I am using plugin with ridge detection, some of red area should not to be accounted by using ridge detection. so should I do?here I attach the my aggregate image. please help me. I am frustated with this.thank you170.tif (4.2 MB)

@tania

To better help you… can you provide a bit more information and context? What exactly are you aiming to do with your analysis? What do you wish to measure? Also - what parameters/settings have you applied thus far in the Ridge Detection plugin?

thank you for reply my message. I want to measure the length of this aggregate. I want to know mean all of aggregate in this image. at the first I already change image into 8 bit image then changing the background by using treshold. after that using plugin then ridge detection. Did I am Wrong?Please help me. it makes me desperate. thank you before.