minor update

README.md

@@ -4,10 +4,13 @@
 CSST L1 pipeline prototype.
 
 ## homepage
-*Gitlab*: [https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto](https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto)
 
+This code is available on *CSST GitLab*:
 
-## install
+[https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto](https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto).
+
+
+## installation
 
 `csst_proto` can be installed with the following shell command
 
@@ -34,11 +37,11 @@ from csst_proto.top_level_interface import flip_image, read_test_image
 from astropy.io import fits
 
 # read an L0 image
-img = fits.getdata("CSST_L0_img.fits")
+img = fits.getdata("CSST_MS_SCI_06_L0_img.fits")
 # flip the image
 img_flipped = flip_image(img=img)
 ```
 
-## algorithm
+## algorithm description
 
 The `csst_proto` uses an awesome algorithm based on `numpy.ndarray` indices to flip images.