System and method to align and merge differently exposed digital images to create a HDR (High Dynamic Range) image

摘要

The present invention provides a system and method to align and merge differently exposed digital images to create a HDR image. In the present system, all the modules starting from the receiving module to fusion module are configured to produce a HDR image with better color purity and sharpness. Each captured image in the system is configured to operate in the HSI color space. The alignment module is configured to align the pixels of each image in a pyramid shaped resolution structure to derive alignment vectors for one or more regional partitions of each image across one or more levels of the pyramid. The system is configured such that, the saturation component in the HSI color space is used to pick the color purity of pixels and intensity channel is used to weigh the sharpness of pixels of each of the differently exposed captured images.

主权项

1. A system to align and merge a plurality of differently exposed digital images to create a HDR image, the system comprising:
a. an embedded camera to capture a bracket of differently exposed digital images, wherein each digital image includes one or more pixel arrays;
wherein the embedded camera comprises:
i. a receiving module configured to receive the bracket of differently exposed digital images;ii. an image restructuring module configured to convert the received images to hue-saturation-intensity (HSI) color space and construct a pyramid shaped resolution structure for intensity channel of each captured image;iii. an alignment module configured to align each pixel of the one or more pixel arrays of each image in the pyramid shaped resolution structure of the intensity channel to derive alignment vectors for one or more regional partitions of each image across one or more levels of the pyramid shaped resolution structure, subsequently effecting a computed alignment vector on a hue and saturation channels;iv. a weight map computation module configured to weigh and qualify the pixels of the image from the alignment module to take into account colour purity and sharpness;v. a motion compensation module configured to detect and compensate artifacts in the qualified pixels due to scene subject motion;vi. a fusion module configured to merge the qualified pixels of the bracket of differently exposed digital images from the motion compensation module to represent a High Dynamic range (HDR) image; andvii. the image restructuring module further converts the HDR image in HSI color space into another color space suitable for rendering/encoding.