diff --git a/CMakeLists.txt b/CMakeLists.txt
index 47ea62c..21ecf44 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -43,9 +43,8 @@ endif()
 # library
 include_directories( include )
 
-# Build runtime load dynamic shared library
-# https://cmake.org/cmake/help/latest/command/add_library.html
-add_library(${PROJECT_NAME} SHARED 
+# all source files
+set( src_files 
   src/align.cpp
   src/bayer_image.cpp
   src/burst.cpp
@@ -53,6 +52,10 @@ add_library(${PROJECT_NAME} SHARED
   src/hdrplus_pipeline.cpp
   src/merge.cpp )
 
+# Build runtime load dynamic shared library
+# https://cmake.org/cmake/help/latest/command/add_library.html
+add_library(${PROJECT_NAME} SHARED ${src_files} )
+
 # and link it
 # https://cmake.org/cmake/help/v3.0/command/target_link_libraries.html
 # use public interace because our .h / .hpp file include opencv .h / .hpp file
@@ -71,17 +74,14 @@ target_link_libraries( demo
 # unit test
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_SOURCE_DIR}/tests )
 
-add_executable( test_bayer_image 
-  tests/test_bayer_image.cpp )
+add_executable( test_bayer_image tests/test_bayer_image.cpp)
 target_link_libraries( test_bayer_image 
   ${PROJECT_NAME} )
 
-add_executable( test_utility 
-  tests/test_utility.cpp )
+add_executable( test_utility tests/test_utility.cpp )
 target_link_libraries( test_utility 
   ${PROJECT_NAME} )
 
-add_executable( test_burst 
-  tests/test_burst.cpp )
+add_executable( test_burst tests/test_burst.cpp )
 target_link_libraries( test_burst 
   ${PROJECT_NAME} )
diff --git a/INSTALL.md b/INSTALL.md
index 9017e67..a792163 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -35,6 +35,7 @@
    ```shell
    mkdir build
    cd build
+   # Default release build will be used
    cmake ..
    make -j 10
    ```
diff --git a/README.md b/README.md
index e06bf7b..9e0efec 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,16 @@
 # HDR+
 > HDR+ Paper reimplementation
+>
 > UC Berkeley Spring 2022 CS184/284A Final Project
+
+
+
+## File Content Overview
+
+```shell
+tests/       # unit test file
+src/         # implementation
+include/     # header file
+bin/demo.cpp # demo to run HDR+ pipeline
+```
+
diff --git a/src/bayer_image.cpp b/src/bayer_image.cpp
index c57b02e..998fa08 100644
--- a/src/bayer_image.cpp
+++ b/src/bayer_image.cpp
@@ -32,10 +32,11 @@ bayer_image::bayer_image( const std::string& bayer_image_path )
     width = int( libraw_processor->imgdata.rawdata.sizes.raw_width );
     height = int( libraw_processor->imgdata.rawdata.sizes.raw_height );
     white_level = int( libraw_processor->imgdata.rawdata.color.maximum );
-    black_level_per_channel[ 0 ] = int( libraw_processor->imgdata.rawdata.color.cblack[ 0 ] + libraw_processor->imgdata.rawdata.color.black );
-    black_level_per_channel[ 1 ] = int( libraw_processor->imgdata.rawdata.color.cblack[ 1 ] + libraw_processor->imgdata.rawdata.color.black );
-    black_level_per_channel[ 2 ] = int( libraw_processor->imgdata.rawdata.color.cblack[ 2 ] + libraw_processor->imgdata.rawdata.color.black );
-    black_level_per_channel[ 3 ] = int( libraw_processor->imgdata.rawdata.color.cblack[ 3 ] + libraw_processor->imgdata.rawdata.color.black );
+    black_level_per_channel.resize( 4 );
+    black_level_per_channel.at( 0 ) = int( libraw_processor->imgdata.rawdata.color.cblack[ 0 ] + libraw_processor->imgdata.rawdata.color.black );
+    black_level_per_channel.at( 1 ) = int( libraw_processor->imgdata.rawdata.color.cblack[ 1 ] + libraw_processor->imgdata.rawdata.color.black );
+    black_level_per_channel.at( 2 ) = int( libraw_processor->imgdata.rawdata.color.cblack[ 2 ] + libraw_processor->imgdata.rawdata.color.black );
+    black_level_per_channel.at( 3 ) = int( libraw_processor->imgdata.rawdata.color.cblack[ 3 ] + libraw_processor->imgdata.rawdata.color.black );
     iso = float( libraw_processor->imgdata.other.iso_speed );
 
     // Create CV mat
diff --git a/tests/README.md b/tests/README.md
new file mode 100644
index 0000000..32c875d
--- /dev/null
+++ b/tests/README.md
@@ -0,0 +1,7 @@
+# Test
+
+```shell
+# ray image
+./test_bayer_image ../dataset/33TJ_20150606_224837_294/payload_N000.dng
+
+```
\ No newline at end of file