[AmebaPro2] Introduction for Switch flow(Day / Night mode)

EVK of AmebaPro2

*ALS = abbreviation for「ambient light sensor」, used to detect environment brightness

*IR-LED = un-visible light, compensate for low light condition

*IR-CUT = control cover glass (remove IR light or not)

• Pin define for IR control

  • IR-CUT: single GPIO

  • IR-LED: PWM

• Initialization for IR control

  • Pin assignment

    • Ref to 「ir_cut.h」 and 「ir_ctrl.h」

  • Initialization and enable function

    • Ref to 「ir_cut.c」 and 「ir_cut.c」

• How to enable IR control

• Ref to 「Platform_opts.h」

Ref to 「Video_example_media_framework.c」

• Pin define for HW-ALS control

  • Through sensor board interface

  • HW-ALS: i2c type

• Initialization for HW-ALS control

  • Pin assignment

    • Ref to 「Ambient_light_sensor.h」

  • Initialization and enable function

    • Ref to 「Ambient_light_sensor.c」

• How to enable HW-ALS control

• Ref to 「Atcmd_isp.c」

• Command: ATIR=init

• Should notice that not to initialize IR control twice

General flow of day/night mode switch

• Switch to 「Day Mode」

  • Disable IR LED

  • Keep IR Filter

  • Set ISP to Day Mode Parameter

  • Set ISP to Color Mode

• Switch to 「Night Mode」

  • Set ISP to Gray Mode

  • Remove IR Filter

  • Enable IR LED

  • Set ISP to IR Mode Parameter

• Refer to 「mmf2_video_example_v1_day_night_change_init.c」

  • This example shows how to set 「IR control」 / 「 ISP 」 / 「 Motion detection 」 configuration during mode switch

  • Switch between both mode without reference to ALS value

General flow of day/night mode switch

Criteria for changing mode

• Criteria to switch between 「Day mode」 and 「Night mode」

  • Refer to Ambient light sensor data

  • HW

    • Through i2c / spi to communicate with sensor

      • RTK EVK use I2C type HW-ALS

    • Detect for luminance strength

      • Same trends to environment luminance

  • SW

    • Through ISP information

    • Detection for luminance strength, compensate for it

      • Opposite from trends to environment luminance

	Bright scene	Dark scene
HW ALS value	↑	↓
SW ALS value	↓	↑

How to use 「HW-ALS 」to active mode change flow

How to active 「HW-ALS」

• Use video example to apply streaming

  • Ex: mmf2_video_example_v1_init()

• Reference code

  • Atcmd_isp.c

    • ATIR=service

• Should initialize IR control before apply sensor_service

• Reference code

sensor_service.c

Select ALS_Type

HW-ALS setting

threshold for mode switch

Reference control flow

「sensor_thread」

How to use 「SW-ALS 」to active mode change flow

How to active 「SW-ALS」

• Use video example to apply streaming

  • Ex: mmf2_video_example_v1_init()

• Reference code

  • Atcmd_isp.c

    • ATIR=service

• Should initialize IR control before apply sensor_service

• Reference code

sensor_service.c

Select ALS_Type

SW-ALS setting

Reference control flow

「sensor_thread」

How to Get SW-ALS Value

• Based on ISP AE Statistic Information

  • Exposure Time

    • isp_get_exposure_time()

  • Gain

    • isp_get_ae_gain()

  • These information both are based on IQ configuration such as AE metering, AE target and stable flow

  • For Example

  • 10ms Exposure time with 5xGain (Bright condition)

    • ALS Value = 100 * 5 = 500

  • 60ms Exposure time with 33.75xGain (Dark condition)

    • ALS Value = 600 * 33.75 = 20250

  • Refer to ISP_Get_ETGAIN()

How to active SW-ALS in amebaPro2

• Debug command

  • ATIR=getlight

    • Get sw-lux value

  • ATIR=als_ver

    • Get SW-ALS algorithm version

  • ATIR=dbg_als,level (level = 0 ~ 3)

    • Enable debug log in als algorithm

  • ATIR=dbg_ss,level (level = 0 ~ 1)

    • Enable debug log in sensor service thread

      • 1: print ALS value & stable information

Introduction for SW-ALS parameter

• ALS THR from RGB Mode to IR Mode

  • Thr_Color_to_Gray

• ALS THR from IR Mode to RGB Mode

  • Thr_Gray_to_Color

• Color ratio to check whether visible light is enough

  • Thr_Color_Ratio

    • This value will be lower when visible light is enough

    • Full IR LED: more close to 256

    • Strong visible light: lower than 192

  • Mask with Thr_Valid_Block

    • Adjust for detection ROI and valid block

• Default parameter (For Circle ring IR LED replacement)

  • Center counting with maximum detection block = 13

  • Valid Block = 6

For IR LED is replaced in bottom of the DUT

Detection in top of frame with maximum block = 12

Valid Block = 6

SW_ALS Tuning

• Test Condition

  • Target: 18% gray wall

  • Distance: 3m

  • Measurement: 3m from camera module

  • Set Environment Luminance to Dark Level (EX: 3 lux)

  • @Day Mode

  • THR_COLOR_TO_GRAY

• Set Environment Luminance to Bright Level (Ex: 8 lux)

  • @IR Mode

  • THR_GRAY_TO_COLOR

• Use ALS debug mode

  • ATIR=dbg_als,2

  • In most case default value would be available

  • Case 1: No visible light with IR LED

  • Case 2: few visible light with IR LED

    • check some ref value is lower than Thr_Color_Ratio

  • Case 3: Enough visible light with IR LED

    • Fit switch criteria and change mode to RGB

Date	Version	A uthor	Release note
2023.04.14	1.0	Zako Wu	Draft version for customer release
2023.06.27	2.0	Zako Wu	Update ALS algorithm for version 2.0
2024.10.30	2.1	Zako	Add flow to active sw-als