GX-MIPI-IMX662 can't save fps parameter

[veye_xumm]

@alex_ai In the current program, HCG will be automatically enabled when the gain is higher than 26 dB — you can give it a try.

Also, please try turning off the 3D noise reduction.

[alex_ai]

@veye_xumm yes, you are right, I checked image in 25 and 26 dB - and it is switching.

Probably I used high digital gain (because brightness low than from IMX462 in same gain value) and it produces high level of noise.

About denoise, in IMX462 I'm using 0x02, but not sure what is MIDDLE value, because in IMX662 denoise_strength_3D with 128 produces different picture and I decreased to 40 to have something similar

0x02	NR 2D Mode = OFF; NR 3D Mode = MIDDLE

Will test couple nights. Thank you.

[veye_xumm]

@alex_ai OK, the GX series and the VEYE series use completely different ISP solutions, so their parameters do not correspond one-to-one. I look forward to your test results.

[alex_ai]

@veye_xumm found what was wrong,
high level of noise produced gamma_index = 1 (default value), other looks good.

[veye_xumm]

@alex_ai Thank you for your feedback; we will look into this issue.

[veye_xumm]

@alex_ai I used firmware version 1.14 for comparison and did not observe any significant noise changes in gamma mode 1 compared to other modes. Could you provide your specific usage parameters and environment?

[alex_ai]

Hi @veye_xumm, I didn't say that this is issue, this parameter needs to be changed only in case video recording of the night sky (meteor detection)

From issues what I noticed:

• can't save fps - always 60 after power on

• Sometimes saved parameters resets to default (noticed when set metime to 33333 but forgot set fps 30 before) and manual expmode switched back to auto

[alex_ai]

Hi @veye_xumm, I'm still trying to configure imx662 for night capturing (meteor detection) and probably you can help me to clarify what is wrong.

I have several cameras from VEYE (imx462 and imx462 mono) and also imx662 mono from another vendor.

And for all cameras configuration pretty same - use 30fps, exposure time 33333 and gain 30Db for mono version and up to 34Db color version (this range approximately within analog gain).

What I see in GX imx662 - for same parameters image too dark, some brightness I can get from gamma_index (with value 5 or 10) but it still not enough

To get required brightness of image I have to increase gain to 45 which leads to boost digital gain and as result more noise, more hot pixels and overbrighted (oversized) stars.

Questions:

1. What could be wrong? (imx662 mono works as expected, not sure it is sensor issue)
2. Can I read sensor registors same as on imx462?

My current config (Raspberry Pi 5, Trixie) :

./gx_mipi_i2c.sh -w fps 30 -b $i2cBus
./gx_mipi_i2c.sh -w expmode 0 -b $i2cBus
./gx_mipi_i2c.sh -w metime 33333 -b $i2cBus
./gx_mipi_i2c.sh -w mgain 34 -b $i2cBus
./gx_mipi_i2c.sh -w denoise_strength_3D 0 -b $i2cBus
./gx_mipi_i2c.sh -w denoise_strength_2D 0 -b $i2cBus
./gx_mipi_i2c.sh -w sharppen 30 -b $i2cBus
./gx_mipi_i2c.sh -w gamma_index 5 -b $i2cBus
./gx_mipi_i2c.sh -w daynightmode 1 -b $i2cBus

Example of image in same time and same parameters (gain 34) for:
GX IMX662

VEYE IMX462

[veye_xumm]

@alex_ai First, let me explain the gain configuration logic for the GX-MIPI-IMX662. The IMX662 features 30dB of Analog Gain and supports High Conversion Gain (HCG). The HCG function acts as an amplification during the sensor's analog signal readout, equivalent to 15.3dB.
Therefore, when we configure the "Again" parameter, the actual range is [0, 45.3dB]. This means you can set the Analog Gain up to 45dB without enabling Digital Gain (Dgain).
Currently, our firmware integrates HCG into the "Again" setting, which may have caused some confusion during your testing.
As for the feature to read sensor registers, I have added it to the development roadmap. It will be provided later via a firmware update package.

[veye_xumm]

@alex_ai

We recently updated the ISP tuning. Please give it a try.

https://wiki.veye.cc/index.php/GX-MIPI-IMX662_Version_Log