5.1 BLC Calibration raw image capture [ISP][Tuning]

[malikshubham19]

In ISPCTSUG document, need more clarification.

Section 5.1 BLC Calibration raw image capture

Step 2. Enable BLC function on sensor

Question: Does it mean that we need to set BLC control registers on sensor to enable the ABLC mode and then capture raw images ? If yes, could you provide some kind of reference for OS08A20 BLC registers settings preferred for this.

Step 4. Take 5 raw for each exposure setting

Question: The instructions mention to capture images at each integration time and a gain. So, Gain 1x, 10ms, 20ms, 30ms, 40ms, 50ms like this for each 1x to 16x gain ? or 10ms to max shutter like 33.33ms or 66.66ms? 

Also, could please tell, why taking raw in different exposure times ? Generally for BLC, images are captured for different gain index.

[malikshubham19]

Why its starts from 10ms ? Generally a sensor shutter is set from 1/3 seconds ~ 1/64000 seconds. If this is a case, why BLC starts from 10ms ? what about 0.01 ms ? or 1 ms ?

[joanxie]

1) you don't need enable this function for senor side, this is for tools

2)I'm not sure if I understand your question, it seems the BLC is related exposure control, for the exposure control, as I known, they controls the integration time and gain, if you need further information about this, pls contact the tools partner to get further information

[malikshubham19]

About raw capture, os08a20 support till 16x. As per instructions, we need to capture 5 raw in each xgain. So, 1x 10ms,20ms,30ms,40ms,50ms then 2x 10ms, 20ms, 30ms, 40ms , 50ms. Am i right ?

[joanxie]

refer to the document "Take 5 raw photos for each of the exposure settings", so from gain1 to gain16, you need set exposure time from 10ms to MAX, if your max is 50ms, then gain1 time 10ms,20ms,30ms,40ms,50ms then gain2 time 10ms, 20ms, 30ms, 40ms , 50ms....gain16 time10ms, 20ms, 30ms, 40ms , 50ms