Depth from focal gradient analysis using object texture removal by albedo normalization

Apparatus for providing a range image of an object, the apparatus comprising:

• structured illumination image acquisition means for acquiring a structured illumination image of the object;
• uniform illumination image acquisition means for acquiring a uniform illumination image of the object;
• albedo-normalization means, connected to the structured illumination image acquisition means and the uniform illumination image acquisition means, for using the structured illumination image of the object and the uniform illumination image of the object to provide an albedo-normalized image;
• and
• processing means, connected to the albedo-normalization means, for processing the albedo-normalized image using a focus measure to provide a focal image that conveys relative range information.

Apparatus for providing a range image of an object, the apparatus comprising:

• a structured illumination image acquirer that provides a structured illumination image of the object;
• a uniform illumination image acquirer that provides a uniform illumination image of the object;
• an albedo-normalizer, connected to the structured illumination image acquirer and the uniform illumination image acquirer, capable of using the structured illumination image of the object and the uniform illumination image of the object to provide an albedo-normalized image;
• and
• a focus measure processor, connected to the albedo-normalizer, capable of processing the albedo-normalized image using a focus measure to provide a focal image that conveys relative range information.

A method for providing a range image of an object, the method comprising the acts of:

• acquiring a first structured illumination image of the object at a first focal position;
• acquiring a first uniform illumination image of the object at the first focal position;
• performing albedo normalization using the first structured illumination image of the object and the first uniform illumination image of the object to provide a first albedo-normalized image;
• processing the first albedo-normalized image using a focus measure to provide a first focal image;
• and
• performing range normalization using the first focal image and a second focal image acquired at a second focal position to provide a relative normalized range image.

Apparatus for providing a range image of an object, the apparatus comprising:

• first structured illumination image acquisition means for acquiring a first structured illumination image of the object at a first focal position;
• first uniform illumination image acquisition means for acquiring a first uniform illumination image of the object at the first focal position;
• albedo-normalization means, connected to the first structured illumination image acquisition means and the first uniform illumination image acquisition means, for using the first structured illumination image of the object and the first uniform illumination image of the object to perform albedo normalization so as to provide a first albedo-normalized image;
• first processing means, connected to the first albedo-normalization means, for processing the first albedo-normalized image using a focus measure to provide a first focal image;
• range normalization means, connected to the first processing means, for performing range normalization using the first focal image and a second focal image at a second focal position to provide a normalized range image.

Apparatus for providing a range image of an object, the apparatus comprising:

• a first structured illumination image acquirer that provides a first structured illumination image of the object at a first focal position;
• a first uniform illumination image acquirer that provides a first uniform illumination image of the object at the first focal position;
• a first albedo-normalizer, connected to the first structured illumination image acquirer and the first uniform illumination image acquirer, capable of using the first structured illumination image of the object and the first uniform illumination image of the object to provide a first albedo-normalized image;
• a first focus measure processor, connected to the first albedo-normalizer, capable of processing the first albedo-normalized image using a first focus measure to provide a first focal image;
• a range image processor, connected to the focus measure processor, capable of using the first focal image and a second focal image at a second focal position to provide a normalized range image.