Abstract: Devices and techniques are generally described for segmentation of image data using depth data. In various examples, color image data may be received from a digital camera. In some examples, depth image data may be received from a depth sensor. In various examples, the depth image data may be separated into a plurality of clusters of depth image data, wherein each cluster is associated with a respective range of depth values. In some further examples, a determination may be made that a first cluster of image data corresponds to an object of interest, such as a human subject, in the image data. In various examples, pixels of the first cluster may be encoded with foreground indicator data. In some further examples, segmented image data may be generated. The segmented image data may comprise pixels encoded with the foreground indicator data.

Abstract: Techniques are described for performing automatic focusing of a projected image on a mobile projection surface. Specific regions of the projected image are identified that are likely to be desired to stay in optimal focus, and attributes of those specific regions, such as sharpness and contrast, can be used to determine the need to refocus the image. Advanced knowledge of the image data being projected can be utilized to determine the specific regions of the projected image that require monitoring for optimal focusing.

Abstract: The present invention relates to information security and discloses a method of establishing public key cryptographic protocols against the quantum computational attack. The method includes the following steps: definition of an infinite non-abelian group G; choosing two private keys in G by two entities; a second entity computing y, and sending y to a first entity; the first entity computing x and z, and sending (x, z) to the second entity; the second entity computing w and v, and sending (w, v) to the first entity; the first entity computing u, and sending u to the second entity; and the first entity computing KA, and the second entity computing KB, thereby reaching a shared key K=KA=KB. The security guarantee of a public key cryptographic algorithm created by the present invention relies on unsolvability of a problem, and has an advantage of free of the quantum computational attack.

Abstract: Techniques are described for performing automatic focusing of a projected image on a mobile projection surface. Specific regions of the projected image are identified that are likely to be desired to stay in optimal focus, and attributes of those specific regions, such as sharpness and contrast, can be used to determine the need to refocus the image. Advanced knowledge of the image data being projected can be utilized to determine the specific regions of the projected image that require monitoring for optimal focusing.

Abstract: Techniques are described for projecting content onto surfaces and for focusing the content. When content is projected by a projector onto a surface, the surface is observed by a camera or other sensor, and the contrast of the projected content is evaluated. The projector then varies its focal point to improve or maximize the observed contrast of the projected content.

Abstract: Techniques are described for detecting a hand gesture made by a user. Fingertips of a hand may be identified and tracked over time. When a user contracts the fingertips from an extended position, hand spread may be calculated based on the area of the hand and fingers. The hand spread over time may be compared to a Gaussian function to evaluate whether the observed motion represents a grasping motion.

Abstract: The present invention relates to information security and discloses a method of establishing public key cryptographic protocols against the quantum computational attack. The method includes the following steps: definition of an infinite non-abelian group G; choosing two private keys in G by two entities; a second entity computing y, and sending y to a first entity; the first entity computing x and z, and sending (x, z) to the second entity; the second entity computing w and v, and sending (w, v) to the first entity; the first entity computing u, and sending u to the second entity; and the first entity computing KA, and the second entity computing KB, thereby reaching a shared key K=KA=KB. The security guarantee of a public key cryptographic algorithm created by the present invention relies on unsolvability of a problem, and has an advantage of free of the quantum computational attack.

Abstract: A method and apparatus (10) for determining a best focus position of an object (30) relative to a reference position (e.g., axis A) of a dark-field optical imaging system (20), with an effective focusing range up to 10 times of the depth of field of the system. The method includes the steps of first forming a dark-field image of the object at different focus positions (zm). Each dark-field image has a corresponding image intensity distribution with an average intensity and a variance of intensity. The next step is forming a set of contrast values by calculating a contrast value (Cm) for each dark-field image based on the variance and the average intensity. The last step is determining the best focus position by fitting a Lorentzian function to the set of contrast values plotted as a function of the different focus positions and identifying the focus position associated with the maximum contract value (Cmax).

Abstract: A method and apparatus (10) for determining a best focus position of an object (30) relative to a reference position (e.g., axis A) of a dark-field optical imaging system (20), with an effective focusing range up to 10 times of the depth of field of the system. The method includes the steps of first forming a dark-field image of the object at different focus positions (zm). Each dark-field image has a corresponding image intensity distribution with an average intensity and a variance of intensity. The next step is forming a set of contrast values by calculating a contrast value (Cm) for each dark-field image based on the variance and the average intensity. The last step is determining the best focus position by fitting a Lorentzian function to the set of contrast values plotted as a function of the different focus positions and identifying the focus position associated with the maximum contract value (Cmax).

Abstract: A light tunnel (24) comprising a hollow light tunnel body (30) or a solid light tunnel body (80) having a central axis (A1 or A2), a reflective surface (42 or 84) facing the axis, and an output end (54 or 94) having an edge (60 or 106) with a chamfered surface (120 or 130) formed on the edge. The chamfered surface is designed to alter the reflective properties of the reflective surfaces of the light tunnel body near the output end so as to reduce or eliminate edge ringing from the light tunnel body edge. In the case of a knife-edge (340) placed at the output end of the light tunnel body, knife-edge ringing is eliminated by providing a light source (310) in the form of a laser with a large number of spatial modes (M2>30). The present invention is expected to be most useful in cases where time-averaging or other interference-eliminating means prove impossible or impractical, such as with applications requiring only one or a few high-irradiance light pulses that need to uniformly irradiate a workpiece.

Abstract: An method of and apparatus (10) for performing laser thermal processing (LTP) of a workpiece (74) having one or more workpiece fields (78). The apparatus includes a pulsed, solid state laser light source (14) having more than 1000 spatial modes (M) and capable of emitting one or more pulses of radiation with a temporal pulse length between 1 nanosecond and 1 microsecond, a workpiece stage (70) for supporting the workpiece, and an illumination optical system having an exposure field (64). The system is arranged between the laser light source and the workpiece stage so as to illuminate within the exposure field at least one of the one or more workpiece fields with the one or more pulses of radiation, with an irradiance uniformity of less than ±5%. The method and apparatus is particularly well-suited for LTP processing of workpieces which require a single pulse or only a few pulses of high-irradiance radiation.