A CMOS Image Readout Circuit with On-Chip Defective Pixel Detection and Correction
Images produced by CMOS sensors may contain defective pixels due to noise, manufacturing errors, or device malfunction, which must be detected and corrected at early processing stages in order to produce images that are useful to human users and image-processing or machine-vision algorithms. This pa...
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MDPI AG
2023-01-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/23/2/934 |
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| author | Bárbaro M. López-Portilla Wladimir Valenzuela Payman Zarkesh-Ha Miguel Figueroa |
| author_facet | Bárbaro M. López-Portilla Wladimir Valenzuela Payman Zarkesh-Ha Miguel Figueroa |
| author_sort | Bárbaro M. López-Portilla |
| collection | DOAJ |
| description | Images produced by CMOS sensors may contain defective pixels due to noise, manufacturing errors, or device malfunction, which must be detected and corrected at early processing stages in order to produce images that are useful to human users and image-processing or machine-vision algorithms. This paper proposes a defective pixel detection and correction algorithm and its implementation using CMOS analog circuits, which are integrated with the image sensor at the pixel and column levels. During photocurrent integration, the circuit detects defective values in parallel at each pixel using simple arithmetic operations within a neighborhood. At the image-column level, the circuit replaces the defective pixels with the median value of their neighborhood. To validate our approach, we designed a <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>128</mn><mo>×</mo><mn>128</mn></mrow></semantics></math></inline-formula>-pixel imager in a <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.35</mn><mspace width="3.33333pt"></mspace><mi mathvariant="sans-serif">μ</mi></mrow></semantics></math></inline-formula>m CMOS process, which integrates our defective-pixel detection/correction circuits and processes images at 694 frames per second, according to post-layout simulations. Operating at that frame rate, our proposed algorithm and its CMOS implementation produce better results than current state-of-the-art algorithms: it achieves a Peak Signal to Noise Ratio (PSNR) and Image Enhancement Factor (IEF) of 45 dB and 198.4, respectively, in images with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.5</mn><mo>%</mo></mrow></semantics></math></inline-formula> random defective pixels, and a PSNR of 44.4 dB and IEF of 194.2, respectively, in images with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.0</mn><mo>%</mo></mrow></semantics></math></inline-formula> random defective pixels. |
| first_indexed | 2024-03-09T11:16:12Z |
| format | Article |
| id | doaj.art-b661e396e8684644b2606894b5cdc195 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-09T11:16:12Z |
| publishDate | 2023-01-01 |
| publisher | MDPI AG |
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| series | Sensors |
| spelling | doaj.art-b661e396e8684644b2606894b5cdc1952023-12-01T00:30:02ZengMDPI AGSensors1424-82202023-01-0123293410.3390/s23020934A CMOS Image Readout Circuit with On-Chip Defective Pixel Detection and CorrectionBárbaro M. López-Portilla0Wladimir Valenzuela1Payman Zarkesh-Ha2Miguel Figueroa3Electrical Engineering Department, University of Concepción, Edmundo Larenas 219, Concepción 4070386, ChileElectrical Engineering Department, University of Concepción, Edmundo Larenas 219, Concepción 4070386, ChileDepartment of Electrical and Computer Engineering (ECE), University of New Mexico, Albuquerque, NM 87131-1070, USAElectrical Engineering Department, University of Concepción, Edmundo Larenas 219, Concepción 4070386, ChileImages produced by CMOS sensors may contain defective pixels due to noise, manufacturing errors, or device malfunction, which must be detected and corrected at early processing stages in order to produce images that are useful to human users and image-processing or machine-vision algorithms. This paper proposes a defective pixel detection and correction algorithm and its implementation using CMOS analog circuits, which are integrated with the image sensor at the pixel and column levels. During photocurrent integration, the circuit detects defective values in parallel at each pixel using simple arithmetic operations within a neighborhood. At the image-column level, the circuit replaces the defective pixels with the median value of their neighborhood. To validate our approach, we designed a <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>128</mn><mo>×</mo><mn>128</mn></mrow></semantics></math></inline-formula>-pixel imager in a <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.35</mn><mspace width="3.33333pt"></mspace><mi mathvariant="sans-serif">μ</mi></mrow></semantics></math></inline-formula>m CMOS process, which integrates our defective-pixel detection/correction circuits and processes images at 694 frames per second, according to post-layout simulations. Operating at that frame rate, our proposed algorithm and its CMOS implementation produce better results than current state-of-the-art algorithms: it achieves a Peak Signal to Noise Ratio (PSNR) and Image Enhancement Factor (IEF) of 45 dB and 198.4, respectively, in images with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.5</mn><mo>%</mo></mrow></semantics></math></inline-formula> random defective pixels, and a PSNR of 44.4 dB and IEF of 194.2, respectively, in images with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.0</mn><mo>%</mo></mrow></semantics></math></inline-formula> random defective pixels.https://www.mdpi.com/1424-8220/23/2/934defective pixeldetection and correction algorithmsimage sensorintegrated circuitintelligent readout circuit |
| spellingShingle | Bárbaro M. López-Portilla Wladimir Valenzuela Payman Zarkesh-Ha Miguel Figueroa A CMOS Image Readout Circuit with On-Chip Defective Pixel Detection and Correction Sensors defective pixel detection and correction algorithms image sensor integrated circuit intelligent readout circuit |
| title | A CMOS Image Readout Circuit with On-Chip Defective Pixel Detection and Correction |
| title_full | A CMOS Image Readout Circuit with On-Chip Defective Pixel Detection and Correction |
| title_fullStr | A CMOS Image Readout Circuit with On-Chip Defective Pixel Detection and Correction |
| title_full_unstemmed | A CMOS Image Readout Circuit with On-Chip Defective Pixel Detection and Correction |
| title_short | A CMOS Image Readout Circuit with On-Chip Defective Pixel Detection and Correction |
| title_sort | cmos image readout circuit with on chip defective pixel detection and correction |
| topic | defective pixel detection and correction algorithms image sensor integrated circuit intelligent readout circuit |
| url | https://www.mdpi.com/1424-8220/23/2/934 |
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