The presence of fine sediment in river gravels is widely recognized as
being detrimental to salmonid habitat quality. In order to facilitate
quantification of sand presence at larger scales, this paper presents
an application of image processing allowing for rapid and accurate
assessments of superficial sand presence in dry exposed fluvial
gravels. Images for the process are acquired with a 35 mm SLR film
camera and then scanned with a desktop scanner. Texture-based
segmentation is then applied to differentiate between sand and clast
areas. Results show that the method is accurate and therefore it offers
an alternative to bulk sampling in cases where rapid assessments of
sand presence are required.