Detection device and detection method using avalanche diode array and calibration matrix generating method thereof
AssigneePixart Imaging Inc.
InventorTso-Sheng TSAI
Life of this patent
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Abstract
There is provided a detection device using a SPAD array including a sensor array, multiple counters, a processor and a frame buffer. The sensor array includes a plurality of SPADs respectively generates an avalanche current while receiving a photon. Each counter counts a number of triggering times of the avalanche current of a corresponding SPAD within an exposure interval. The frame buffer is pre-stored with a plurality of gain calibration values corresponding to every SPAD of the sensor array. The processor accesses the gain calibration values to accordingly calibrate a counting image frame outputted by the sensor array to output a calibrated image frame.
Claims19
A detection device, comprising:
- a sensor array, comprising a plurality of single photon avalanche photon diodes (SPADs) arranged in an array, the plurality of SPADs respectively configured to trigger an avalanche current while receiving a photon;
- multiple counters, each configured to count a number of triggering times of the avalanche current of a corresponding SPAD within an exposure interval;
- a frame buffer, configured to store a calibration matrix, which includes a plurality of gain calibration values corresponding to every SPAD of the sensor array;
- and
- a processor, configured to access the calibration matrix from the frame buffer to accordingly calibrate a counting image frame outputted by the sensor array and output a calibrated image frame.
A detection method of a detection device, the detection device comprising a sensor array, multiple counters, a frame buffer and a processor, the frame buffer storing a calibration matrix, and the detection method comprising:
- counting, by the multiple counters, a number of triggering times of an avalanche current of every single photon avalanche diode (SPAD) column of the sensor array to generate a counting image frame;
- reading, by the processor, the calibration matrix from the frame buffer, the calibration matrix comprising a plurality of gain calibration values corresponding to every SPAD of the sensor array;
- and
- dividing, by the processor, each count value of the number of triggering times of the counting image frame by the gain calibration value of a corresponding position in the calibration matrix to generate a calibrated image frame.
A generating method of a calibration matrix for a single photon avalanche diode (SPAD) array, the generating method comprising:
- illuminating, by a light source, the SPAD array for a first exposure interval using light intensity;
- counting a number of triggering times of an avalanche current of a plurality of SPADs of the SPAD array within the first exposure interval to generate a first count matrix;
- illuminating, by the light source, the SPAD array for a second exposure interval using the same light intensity;
- counting a number of triggering times of an avalanche current of the plurality of SPADs of the SPAD array within the second exposure interval to generate a second count matrix;
- calculating a count difference matrix between the second and first count matrices, and a time difference between the second and first exposure intervals;
- and
- calculating a ratio between each count difference of the count difference matrix and the time difference as the calibration matrix.
A generating method of a calibration output for a single photon avalanche diode (SPAD) array, the generating method comprising:
- exposing the SPAD array for a first exposure interval at an illuminating intensity to generate a first output data;
- exposing the SPAD array for a second exposure interval at the same illuminating intensity to generate a second output data;
- calculating an output difference between the second and first output data, and a time difference between the second and first exposure intervals;
- and
- calculating a ratio between each count difference, corresponding to each SPAD of the SPAD array, of the output difference and the time difference as the calibration output.
Dependencies are inferred from the claim text.