Method and tool for surface texture evaluation
OwnerAhmed Shalaby, Amin El Gendyinventors
Life of this patent
Estimating the term…
Abstract
Texture of a surface, for example concrete, is evaluated by capturing images of the surface facing the surface in a direction of an orthogonal axis extending perpendicularly from the surface while sequentially projecting light onto the surface from each of four light source positions spaced circumferentially about the orthogonal axis. A specularity condition is determined to exist in one of the four images by comparing intensities of the images directly with one another. If a specularity condition exists, three images of the four images which are least affected by specularity are used to determining a surface gradient of the surface.
Claims20
A method of evaluating texture of a surface, the method comprising:
- providing an image capturing device arranged to capture an image;
- providing a source of light arranged to project light in a lighting direction;
- locating the image capturing device along an orthogonal axis extending perpendicularly from the surface and facing the surface in a direction of the orthogonal axis so as to be arranged to capture an image of the surface;
- sequentially projecting light onto the surface from each of four light source positions spaced circumferentially about the orthogonal axis;
- arranging the lighting direction to be at a constant angle of inclination relative to the orthogonal axis in each of the four light source positions;
- arranging an intensity of the projected light to be constant in each of the four light source positions;
- capturing four images of the surface using the image capturing device in which the surface is illuminated by the light source from a respective one of the four lighting positions when each of the four images are captured;
- determining if a specularity condition exists in one of the four images by comparing intensities of the images directly with one another;
- if a specularity condition exists:
- i) determining three images of the four images which are least affected by specularity;
- and
- ii) determining a surface gradient of the surface using the three images.
A method of evaluating texture of a surface, the method comprising:
- providing an image capturing device arranged to capture an image;
- providing a source of light arranged to project light in a lighting direction;
- locating the image capturing device along an orthogonal axis extending perpendicularly from the surface and facing the surface in a direction of the orthogonal axis so as to be arranged to capture an image of the surface;
- sequentially projecting light onto the surface from each of four light source positions spaced circumferentially about the orthogonal axis;
- arranging the lighting direction to be at a constant angle of inclination relative to the orthogonal axis in each of the four light source positions;
- arranging an intensity of the projected light to be constant in each of the four light source positions;
- capturing four images of the surface using the image capturing device in which the surface is illuminated by the light source from a respective one of the four lighting positions when each of the four images are captured;
- including:
- determining if a shadow condition exists in one of the four images by comparing intensities of the images to a prescribed threshold;
- and
- if a shadow condition exists:
- i) determining three images of the four images which are least affected by shadow;
- and
- ii) determining a surface gradient of the surface using the three images.
Dependencies are inferred from the claim text.