Why I take a dark photo

[DeikiChen]

Hello,
I use a raspberry pi 3b and a CSI camera to run this demo.
When I take pictures,the images are very dark,just like exposure not enough.
How can I fix this issues?

[shubhamshekhar]

I am facing the same problem. The image which is being captured by camera module is very dark. Kindly provide us with a solution to fix this issue