Image data of a light source comprising a surface is obtained using an optical sensor. The surface includes a color band code comprising an array of color regions at least partially modifying visible light of the light source prior to the light impinging the optical sensor. One or more characteristics of the color band code are determined based on the image data that is obtained. Determining a unique identity of the light source based on the determined one or more characteristics of the color band code is performed, or determining a location within a structure associated with the light source based on the determined one or more characteristics of the color band code is performed.

Techniques are described for selective extraction of color attributes from digital images that overcome the challenges experienced in conventional systems for color extraction. In an implementation, a user applies a region selector to a source image to select a portion of the source image for color attribute extraction. A graphics editing system identifies a selected region of the source image as well as visual objects of the source image included as part of the selected region. The graphics editing system iterates through the selected visual objects and extracts color attributes from the visual objects, such as color values, patterns, gradients, gradient stops, opacity, color area, and so forth. The graphics editing system then generates a color palette that includes the extracted color attributes, and the color palette is able to be utilized for various image editing tasks, such as digital image creation and transformation.

Techniques are described for selective extraction of color attributes from digital images that overcome the challenges experienced in conventional systems for color extraction. In an implementation, a user applies a region selector to a source image to select a portion of the source image for color attribute extraction. A graphics editing system identifies a selected region of the source image as well as visual objects of the source image included as part of the selected region. The graphics editing system iterates through the selected visual objects and extracts color attributes from the visual objects, such as color values, patterns, gradients, gradient stops, opacity, color area, and so forth. The graphics editing system then generates a color palette that includes the extracted color attributes, and the color palette is able to be utilized for various image editing tasks, such as digital image creation and transformation.

An imaging control method is provided. The method may include obtaining a current image generated based on an exposure parameter, wherein the current image includes a plurality of pixels; determining a plurality of target pixels or target pixel groups from at least portion of the plurality of pixels; determining a statistic representation based on target pixels or target pixel groups; determining a characteristic feature based on the statistic representation; and, updating the exposure parameter, based on the characteristic feature, to generate an updated image.

An imaging control method is provided. The method may include obtaining a current image generated based on an exposure parameter, wherein the current image includes a plurality of pixels; determining a plurality of target pixels or target pixel groups from at least portion of the plurality of pixels; determining a statistic representation based on target pixels or target pixel groups; determining a characteristic feature based on the statistic representation; and, updating the exposure parameter, based on the characteristic feature, to generate an updated image.

A method for generating a highly distinctive signature of a certain diamond, the method may include generating, based on one or more images of the certain diamond, a certain diamond signature of the certain diamond; finding, out of a group of reference diamonds, other diamonds having other diamond signatures; wherein the finding comprises calculating similarities between the certain diamond signature and reference diamond signatures of the reference diamonds of the group; and generating a new certain diamond signature that significantly differs from signatures of the other diamonds.

A method for generating a highly distinctive signature of a certain diamond, the method may include generating, based on one or more images of the certain diamond, a certain diamond signature of the certain diamond; finding, out of a group of reference diamonds, other diamonds having other diamond signatures; wherein the finding comprises calculating similarities between the certain diamond signature and reference diamond signatures of the reference diamonds of the group; and generating a new certain diamond signature that significantly differs from signatures of the other diamonds.

A facial verification method includes separating a query face image into color channel images of different color channels, obtaining a multi-color channel target face image with a reduced shading of the query face image based on a smoothed image and a gradient image of each of the color channel images, extracting a face feature from the multi-color channel target face image, and determining whether face verification is successful based on the extracted face feature.

A facial verification method includes separating a query face image into color channel images of different color channels, obtaining a multi-color channel target face image with a reduced shading of the query face image based on a smoothed image and a gradient image of each of the color channel images, extracting a face feature from the multi-color channel target face image, and determining whether face verification is successful based on the extracted face feature.

Systems and methods for detecting data acquisition conditions using color-based penalties can include a computing device obtaining a sequence of images acquired by a photodetector. The computing device can determine, for each pixel position of a plurality of pixel positions associated with the sequence of images, a respective penalty score indicative of a similarity between a color value of a pixel of the pixel position and a desired color value. The desired color value can represent a color property of light emitted from body parts of users when placed opposite to the photodetector. The computing device can determine, using penalty scores of the plurality of pixel positions, a relative position of a body part of a user with respect to a desired position.