Optical sensor capable of synchronizing to ambient light flicker
AssigneePixart Imaging Inc.
InventorsZi-Hao TAN, Joon-Chok LEE
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Abstract
There is provided an optical sensor including a photodiode, a wave converter, a pixel array and a processor. The photodiode detects ambient light flicker to generate sine waves. The wave converter converts the sine waves to square waves. The processor uses a sampling frequency to count the square waves, and identifies whether the ambient light flicker is well detected according to a counting value of each square wave and a counting value variation of multiple square waves within a count period to accordingly determine whether to adjust an acquiring phase of the image frame.
Claims20
An optical sensor, comprising:
- a photodiode, configured to detect ambient light flicker to generate a sine wave signal;
- a wave converter, configured to convert the sine wave signal to a square wave signal;
- a pixel array, configured to acquire image frames according to frame ticks;
- and
- a digital backend, configured to count the square wave signal using a sampling frequency, and generate a trigger tick for adjusting the frame ticks according to a counting value of every square wave signal within a count period as well as consistency of multiple counting values of all square wave signals within the count period.
An optical sensor, comprising:
- a photodiode, configured to detect ambient light flicker to generate a sine wave signal;
- a wave converter, configured to convert the sine wave signal to a square wave signal;
- a pixel array, configured to acquire image frames according to frame ticks;
- and
- a digital backend, configured to
- count a counting value of every square wave signal within a count period,
- synchronize the image frames to the ambient light flicker when identifying that the counting value of every square wave signal is within two predetermined thresholds as well as a difference value between a maximum counting value and a minimum counting value among multiple counting values of all square wave signals within the count period is within a predetermined range, and
- not synchronize the image frames to the ambient light flicker when identifying that not every square wave signal within the count period has the counting value within the two predetermined thresholds or the difference value between the maximum counting value and the minimum counting value among the multiple counting values exceeds the predetermined range.
An optical sensor, comprising:
- a photodiode, configured to detect ambient light flicker to generate a sine wave signal;
- a wave converter, configured to convert the sine wave signal to a square wave signal having a square wave period;
- a pixel array, configured to acquire image frames using a frame period;
- and
- a digital backend, configured to
- count a counting value of every square wave signal within a count period using a sampling frequency,
- adjust a phase of a secondly acquired image frame of a next count period behind the count period when the frame period is equal to the square wave period as well as a trigger tick is generated, and
- adjust a phase of a firstly acquired image frame of the next count period behind the count period when the frame period is multiple times of the square wave period as well as the trigger tick is generated.
Dependencies are inferred from the claim text.