Home Page       Mon Dec 1 02:11:21 JST 1997

Conclusion

In this article I described the method of field flattening and original pixel value restoration of level corrected images. Field flattening cannot be done only using pixel values themselves generally. But I showed that images can be flattened using the variance of noises. I also showed the method restores the original pixel value before level correction.

As results of experiments, there are some cases which the image could not be flattened well in. The reason for the failure is uncertain now. The restoration of linearity between magnitude and pixel value will influence to matching between the image and the catalog or photometry of detected new objects. Though I described the linearity is restored well in this article, there are many stars whose brightness is much different between on the image and in the catalog, or even among catalogs. So I cannot say anything with the cases of several stars actually. I will describe more precisely on the relation of magnitude and pixel value in another article.