Our Blog
Research >> Single Sensor Cameras
DescriptionMost consumer digital cameras capture colour images using a single light sensor and a colour filter array (CFA). This results in a mosaic image being captured, where at each pixel location either a red, green, or blue sample is obtained. The two missing colours at each location must be interpolated from the surrounding samples in a process known as demosaicking. In most current digital cameras, demosaicking is carried out in RGB colour space and later the image or video is converted to YCbCr 4:2:0 format and compressed with standard methods. Most previous research on demosaicking and compression in digital cameras has addressed the issues separately. That is, demosaicking methods ignore the fact that the data will later be compressed, and compression techniques ignore the fact that the data was captured with a CFA.
We have developed methods for improving the demosaicking and compression processes in digital cameras that take into account that fact that both steps need to be performed. We have designed a fast demosaicking method that directly produces an image in YCbCr 4:2:0 format. This reduces the computational complexity relative to the conventional approach of performing demosaicking in the RGB space and later converting to YCbCr 4:2:0 format. We have also developed methods for compressing video captured with a CFA prior to demosaicking being performed. This allows us to take advantage of the smaller input data size, improving the compression efficiency.
Researchers
Selected Publications:
- C. Doutre and P. Nasiopoulos, "Modified H.264 Intra Prediction for Compression of Video and Images Captured with a Color Filter Array", IEEE International Conference on Image Processing (ICIP 2009), Cario, Egypt, pp. 3401-3404, Nov. 2009.
- C. Doutre, P. Nasiopoulos, and K.N. Plataniotis, "H.264 Based Compression of Bayer Pattern Video Sequences." IEEE Transactions on Circuits and Systems for Video Technology, vol. 18, no. 6, pp. 725-734, Jun. 2008.
- C. Doutre and P. Nasiopoulos, "Analysis of the Impact of Demosaicking on JPEG Image Compression," IEEE Workshop on Image Analysis for Multimedia Interactive Services (WIAMIS 2007), Santorini, Greece, pp. 71-74, Jun. 2007.
- C. Doutre, P. Nasiopoulos, and K.N. Plataniotis, "A Fast Demosaicking Method Directly Producing YCbCr 4:2:0 Output." IEEE Transactions on Consumer Electronics, vol. 53, no. 2, pp. 499-505, May 2007.
- C. Doutre and P. Nasiopoulos, "An Efficient Compression Scheme for Colour Filter Array Images Using Estimated Colour Differences," IEEE Canadian Conference on Electrical and Computer Engineering (CCECE 2007), Vancouver, Canada, pp. 24-27, Apr. 2007.
- C. Doutre and P. Nasiopoulos, "An Efficient Compression Scheme for Colour Filter Array Video Sequences," IEEE International Workshop on Multimedia Signal Processing (MMSP-2006), Victoria, Canada, pp. 166-169, Oct. 2006.