Simple method for calculating camera defocus from an image scene
First Claim
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1. A computerized method comprising:
- receiving an auto focus curve that is associated with a picture of a three dimensional spatial scene, wherein the auto focus curves comprises a step edge; and
computing a picture depth value based on the step edge and an auto focus normalization reference curve, wherein the auto focus normalization reference curve correlates the step edge to a known amount of blurring and the computing the picture depth value comprises detecting the step edge in the auto focus curve, shifting the step edge to have a baseline of zero;
computing a one dimensional gradient of the step edge;
locating a center of the step edge;
computing a defocus measurement value for the step edge based on the one dimensional step edge and step edge center;
deriving a picture blur value based on the defocus measurement value and the auto focus normalization reference curve; and
computing the picture depth value based on the picture blur value.
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Abstract
An imaging acquisition system that generates a picture depth from an auto focus curve generated from picture of a three dimensional spatial scene is described. The auto focus curve comprises a step edge. The system generates the depth based on the step edge and a reference auto focus normalization curve.
64 Citations
20 Claims
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1. A computerized method comprising:
- receiving an auto focus curve that is associated with a picture of a three dimensional spatial scene, wherein the auto focus curves comprises a step edge; and
computing a picture depth value based on the step edge and an auto focus normalization reference curve, wherein the auto focus normalization reference curve correlates the step edge to a known amount of blurring and the computing the picture depth value comprises detecting the step edge in the auto focus curve, shifting the step edge to have a baseline of zero;
computing a one dimensional gradient of the step edge;
locating a center of the step edge;
computing a defocus measurement value for the step edge based on the one dimensional step edge and step edge center;
deriving a picture blur value based on the defocus measurement value and the auto focus normalization reference curve; and
computing the picture depth value based on the picture blur value. - View Dependent Claims (2, 3, 4, 5, 6)
- receiving an auto focus curve that is associated with a picture of a three dimensional spatial scene, wherein the auto focus curves comprises a step edge; and
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7. A machine readable medium having executable instructions to cause a processor to perform a method comprising:
- receiving an auto focus curve, that is associated with a picture of a three dimensional spatial scene, wherein the auto focus curves comprises a step edge; and
computing a picture depth value based on the step edge and an auto focus normalization reference curve, wherein the auto focus normalization reference curve correlates the step edge to a known amount of blurring and the computing the picture depth value comprises detecting the step edge in the auto focus curve;
shifting the step edge to have a baseline of zero;
computing a one dimensional gradient of the step edge;
locating a center of the step edge;
computing a defocus measurement value for the step edge based on the one dimensional step edge and step edge center;
deriving a picture blur value based on the defocus measurement value and the auto focus normalization reference curve; and
computing the picture depth value based on the picture blur value. - View Dependent Claims (8, 9, 10, 11, 12)
- receiving an auto focus curve, that is associated with a picture of a three dimensional spatial scene, wherein the auto focus curves comprises a step edge; and
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13. An apparatus comprising:
- means for receiving an auto focus curve, that is associated with a picture of a three dimensional spatial scene, wherein the auto focus curves comprises a step edge; and
means for computing a picture depth value based on the step edge and an auto focus normalization reference curve wherein the auto focus normalization reference curve correlates the step edge to a known amount of blurring and the means for computing the picture depth value further comprises means for detecting the step edge in the auto focus curve;
means for shifting the step edge to have a baseline of zero;
means for computing a one dimensional gradient of the step edge;
means for locating a center of the step edge, means for computing a defocus measurement value for the step edge based on the one dimensional step edge and step edge center;
means for deriving a picture blur value based on the defocus measurement value and the auto focus normalization reference curve; and
means for computing the picture depth value based on the picture blur value. - View Dependent Claims (14, 15, 16)
- means for receiving an auto focus curve, that is associated with a picture of a three dimensional spatial scene, wherein the auto focus curves comprises a step edge; and
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17. A system comprising:
- a processor;
a memory coupled to the processor though a bus; and
a process executed from the memory by the processor to cause the processor to receive an auto focus curve, that is associated with a picture of a three dimensional spatial scene, wherein the auto focus curves comprises a step edge; and
compute a picture depth value based on the step edge and an auto focus normalization reference curve, wherein the auto focus normalization reference curve correlates the step edge to a known amount of blurring and the process further causes the processor to detect the step edge in the auto focus curve, shift the step edge to have a baseline of zero, compute an one dimensional gradient of the step edge, locate a center of the step edge, compute a defocus measurement value for the step edge based on the one dimensional step edge and step edge center, derive a picture blur value based on the defocus measurement value and the auto focus normalization reference curve, and compute the picture depth value based on the picture blur value. - View Dependent Claims (18, 19, 20)
- a processor;
Specification