发明名称 |
Optical black-level cancellation for optical sensors using open-loop sample calibration amplifier |
摘要 |
A Optical Black Pixel (OBP) cancellation circuit corrects offsets in sensors in a CCD/CMOS image sensor when reading dark pixels such at the periphery. A pixel voltage is switched to a sampling capacitor during two phases of the same pixel pulse. Sampling capacitors and feedback capacitors connect to differential inputs of an amplifier. An accumulating capacitor accumulates voltage differences and generates a common-mode voltage that is fed back to another sampling capacitor that stores an amplifier offset. The sampling capacitor and accumulating capacitor and their associated switches form a discrete-time first-order low-pass filter that filters the pixel voltage during the first phase. In the second phase the amplifier acts as a unity-gain amplifier to output an average of the pixel voltage differences generated during an OBP time when blackened or covered pixels are read from the image sensor. |
申请公布号 |
US8179455(B2) |
申请公布日期 |
2012.05.15 |
申请号 |
US20100722148 |
申请日期 |
2010.03.11 |
申请人 |
LEUNG LAP CHI (DAVID);LAI YAT TUNG;WONG CHUN FAI;CHAN KAM HUNG;KWONG KWOK KUEN (DAVID);HONG KONG APPLIED SCIENCE AND TECHNOLOGY RESEARCHINSTITUTE CO., LTD. |
发明人 |
LEUNG LAP CHI (DAVID);LAI YAT TUNG;WONG CHUN FAI;CHAN KAM HUNG;KWONG KWOK KUEN (DAVID) |
分类号 |
H04N5/217 |
主分类号 |
H04N5/217 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|