Image stabilization techniques have been used in a Wide variety of different applications, including surveillance applications, vehicle-mounted image sensor applications, robotics applications, and consumer electronics applications. Image stabilization is the process of eliminating or at least reducing the effects of unWanted image sensor motion (e.g., unWanted image sensor vibration or irregular image sensor motion) on still images or video sequences. Many image stabilization approaches attempt to eliminate or at least reduce the amount of unWanted image sensor motion relative to a scene While preserving any intentional image sensor motion. In this regard, these image stabilization techniques synthesize a neW image or video sequence from the perspective of a stabilized image sensor trajectory.
Among the primary classes of image stabilization techniques are mechanical image stabilization methods, electromechanical image stabilization methods, optical image stabilization methods, and electronic image stabilization methods. Mechanical image stabilization systems attempt to dampen the motion of the image sensor (or just the lens/ image sensor subsystem). Electromechanical image stabilization systems detect motion of the image sensor using, for example, an inertial sensor, and alter the position or orientation of the image sensor to offset the detected image sensor motion. Optical image stabilization approaches stabilize the image of the sensor by displacing the image as it is formed by the lens system in a Way that offsets image sensor motion. Electronic image stabilization techniques involve modifying the captured images in Ways that makes the captured images appear to have been captured by a more stable image sensor.
Many image stabilization techniques are not suitable for compact camera environments, such as handheld electronic devices (e.g., mobile telephones), cameras designed for desktop and mobile computers (often referred to as “pc cameras”), and other embedded environments. For example, optical image stabilization techniques require large and bulky components that cannot be accommodated in most compact camera environments. Electronic image stabilization techniques, on the other hand, are computationally intensive and require significant memory resources, making them unsuitable in compact application environments in Which processing and memory resources typically are significantly constrained.
What are needed are systems and methods of reducing motion-induced blur in still images Within the significant size, processing, and memory constraints of typical compact camera environments.
In one aspect, the invention features an apparatus that includes an image sensor, a motion sensor, and a processing system. The image sensor is operable to capture image segments during corresponding exposure intervals of a frame exposure period. The motion sensor is operable to generate respective motion sensor signals during the respective exposure intervals of the image segments. The processing system is operable to determine from the respective motion sensor signals one or more corresponding movement measures for each of the exposure intervals and combine the image segments into an output image based on the one or more corresponding movement measures.