Differentiate table line from big letters

I'm doing some graphics processing and I have a logic where in I have a bitmap with edges and I disregard all table edges from the letters E.g.

0 - background color
1 - ignored edges
2 - edges I need

My logic is just simple, if a number of continuous pixels exceeds a certain threshold, e.g. 20pixels of continuous edges, it will consider it as a line and disregard it.

My problem is that on big font size and letters such as H and T, it will definitely exceed the threshold. Please advise is there a better way or additional logic i need to implement in order to separate table lines from letters.

[update] Additional consideration: Performance, this logic will be used during touch movement (dragging). It will be called a lot of times so it needs to be fast.

Solution

If table lines are guaranteed to be thin, then ignore thick lines. However, if the lines in your application are generated by edge detection (which are always 1-pixel thin) then connected-component will be needed.

Basically, the "thickness" refers to thickness measured from an edge profile:

00000000100000000 This line has thickness 1
00000011111000000 This line has thickness 5. However, this cannot occur in the output of edge detection, because edge detection algorithms are specifically designed to remove this condition.
00000000111111111 This is a transition from black to white.

Table lines usually have small thickness. Large fonts usually have transition from black to white because their thickness is larger than the edge profile window.