How to manufacture a low-cost digital still camera (DSC) that can meanwhile provide a good image quality is always an engineering challenge. For this purpose, the color filter array (CFA) is perhaps the most commonly used structure for modern DSCs. However, since most of the color information is filtered out, a good interpolation process is required to retrieve the original image. Many interpolation methods have thus been proposed. In this work, we propose to perform the edge-preserving signal correlation based (EP-SCB) interpolation  as a second pass to those images restored from some other existing interpolation methods such as local polynomial approximation intersection of confidence intervals (LPA-ICI) rule . Experiments show that most of the images' PSNRs can be improved by the second pass. The simplicity of the EP-SCB hence makes it a suitable candidate as an enhancement option for DSCs techniques.