White object on white background filtering

[dkt64]

Hi.

I have a problem with finding edge of the object. Object is white and the background is white. But, object and background have different surface porosity. Object has some pores (on entire surface) and background is more flat (shiny a little bit).

I'm wondering about using filter (polarized?) to get different grey level between object and background. Then I could find the object and the edges.

What do you suggest in such situations?

Bartosz

[altenbach]

It is difficult to tell from your limited description. Is the "object" 2D and aligned flat with the background? Does it have a known size/shape/orientation? How many edges are there to find? Is the object 3D? How much control do you have about lighting?  How about using infrared, for example?

Can you show us a sample image?

[dkt64]

Hi.

I want to measure the dimensions of boxes.

The most problem is with the box placed on white band.

The lighting can change (strong sunlight during a day, neon lamps during a night) so during day we get the same white reflection from box and band. In that situation we can't find the edge (bottom side on photo "right29_2.png") and measure the box.

No additional light accepted, no moving cameras, we use stereo cameras to make photos.

I'm thinking about using filters because polarization filter could block more light reflected from the box (porous surface) than from flat white band. I'm wondering what experts think about?

Thanks,

Bartosz.