Digital camera focus self-calibration

Abstract

Focus self-calibration for a digital camera may be performed by moving a lens assembly of the digital camera over its travel range, and detecting travel limits of the lens assembly based on audio signal generated by the lens assembly reaching ends of the travel range. Digital-to-analog converter values corresponding to the lens assembly at the ends of the travel range may be used to create a camera focus profile.

Description

BACKGROUND[0001]In addition to digital cameras, digital camera function is widely available as a built-in function for many portable electronic devices such as cellular phones, tablet computers, and laptop computers. These portable electronic devices are often taken with users and experience changing environment and conditions during their use. For instance, a user may take photographs using the digital camera function of a cellular phone over a wide range of temperatures and orientations. Many components, including lenses, are commonly made of plastic material and are susceptible to thermal expansion and contraction. Depending on the orientation of the portable electronic device, gravity may have a different effect on movable components, such as a lens assembly for focusing, and a different amount force may be needed to move the lens assembly depending on the orientation of the portable electronic device. For instance, if gravity is acting in a direction opposite of a direction of ...

AI Technical Summary

Benefits of technology

This patent describes a method for calibrating a digital camera using a portable electronic device with microphones. The microphones detect the first and second audio signals when the lens assembly reaches the ends of its travel range, and the digital-to-analog converter values are recorded. Based on these values, the current condition of the device and pre-stored lens assembly travel profiles, an appropriate lens assembly travel profile is accessed and revised to calibrate the camera. The technical effect is that this method provides a convenient and efficient way to calibrate a digital camera, regardless of its location or orientation.

Problems solved by technology

Many components, including lenses, are commonly made of plastic material and are susceptible to thermal expansion and contraction.

However, such a specific profile may not always correspond to actual use conditions.

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