Digital Image Segmentation Using Flash
AssigneeTexas Instruments Incorporated
InventorLeonardo William Estevez
Life of this patent
Estimating the term…
Abstract
A digital camera function, such as can be implemented in a cellular telephone handset, and that includes automated segmentation of foreground subjects in acquired digital photos and images. Successive images are captured by the digital camera function at different flash exposure levels, for example using existing light only and using flash exposure. After alignment and registration of the images, luminance difference values in the two images are determined for each pixel, and the luminance difference values compared against a threshold value on a pixel-by-pixel basis. Those pixels with luminance difference values exceeding the threshold are segmented from the image as foreground subjects.
Claims24
A segmentation method for identifying one or more subjects in a digital image according to distance, comprising the steps of:
- capturing a first digital image of a scene including first and second subjects at different distances from the point of view of the captured image, at a first flash exposure level;
- capturing a second digital image of the scene including the first and second subjects, at a second flash exposure level different from the first flash exposure level;
- determining a luminance difference for pixels corresponding to the first and second subjects, between the first and second digital images;
- and
- identifying those pixels having a luminance difference relative to a threshold luminance difference value, as pixels corresponding to the first subject.
An electronic system, comprising:
- camera hardware, including a lens and electronic shutter;
- a camera flash;
- circuitry for controlling the electronic shutter and camera flash in capturing a digital image;
- processor circuitry for processing digital data corresponding to images acquired via the camera hardware;
- program memory, for storing software instructions that, when executed by the processor circuitry, cause the processor circuitry and controlling circuitry to perform a sequence of operations comprising:
- causing the camera hardware and camera flash to capture a first digital image of a scene including first and second subjects at different distances from the point of view of the captured image, at a first flash exposure level;
- causing the camera hardware and camera flash to capture a second digital image of the scene including the first and second subjects, at a second flash exposure level different from the first flash exposure level;
- determining a luminance difference for pixels corresponding to the first and second subjects, between the first and second digital images;
- and
- identifying those pixels having a luminance difference relative to a threshold luminance difference value as pixels corresponding to the first subject.
Dependencies are inferred from the claim text.