ASI 533 pictures stored as B&W - wanted color

dvachon1

Hoping someone can help me with my problem. I have an ASI533MC Pro color camera. I use NINA software to take images. In the stretched preview, the image is in color but the stored image is B&W. Anybody else run into this issue? How was it fixed?

w7ay

dvachon1 ASI533MC Pro color camera. I use NINA software to take images. In the stretched preview, the image is in color but the stored image is B&W.

The only native color CMOS camera, where each and every pixel has three color components, uses the Foveon sensor.

All others, including the Sony sensors used by ZWO are monochrome cameras with a layer of micro color filters on them in a Bayer mosaic. Each pixel from the camera is either a "green," "red," or "blue" pixel, and just has an intensity value. If you magnify the image, you will see the Bayer structure looking like a grid pattern.

After reading out the data, you need to "deBayer" the camera data into a color image. Debayering is done during post processing, and the step which you did not perform.

Chen

dvachon1

Thanks. What software do you use to debayer? Do you debayer each image before stacking or debayer the stacked image?

w7ay

dvachon1 What software do you use to debayer?

Pretty much all readers that process FITS format will have a debayering option since the Bayer pattern is included in the FITS meta data ("headers"). The debayering process will typically lose a little of resolution (can't get around Shannon-Nyquist-Whittaker theorem) compared to a monochrome camera with color separation filters However, many astrophotography programs take advantage of dithering (or imperfect tracking) to recover the full resolution by using a stack of images with Drizzle-like algorithms.

If you don't really care about image quality, you can even use the naive debayering in the ASIFitsView tool in ZWO's ASIStudio package -- it is free, and as usual, you get what you pay for. You can change the FITS files into color RGB TIFF files. Programs such as AstroPixelProcessor have the Drizzle debayering option when you give them a bunch of dithered images to stack.

Chen