VD66GY + Rockchip RV1106 ISP – Green color cast and low saturation, need sensor tuning guidance

[satishkatti]

 

Hi ST team,

I am using the ST VD66GY image sensor connected to a Rockchip RV1106 processor with the Rockchip hardware ISP.

I have successfully enabled the camera pipeline and can capture images, but the image quality has a strong greenish color cast and the colors look desaturated, even under a bright indoor room with white LED lighting.

Current setup

• Sensor: ST VD66GY

• Processor: Rockchip RV1106

• ISP: Rockchip RKISP (hardware ISP)

• Capture: RAW from VD66GY → RKISP → Image output

Observed issue

• Strong green tint across the entire image

• Skin tones appear gray/green

• Low color saturation

• Indoor lighting is much brighter than what the captured image suggests

I have attached three sample images captured with the current ISP settings.

Questions

1. Does ST provide an IQ tuning file or reference tuning parameters for VD66GY when used with a third-party ISP such as Rockchip RKISP?

2. Are there recommended AWB calibration, Color Correction Matrix (CCM), or Lens Shading Correction (LSC) values for this sensor?

3. Is the green cast typically caused by missing sensor calibration data, or should it be corrected entirely through ISP tuning?

4. Is there any recommended register configuration for VD66GY that improves color reproduction before ISP processing?

Any guidance or reference tuning data would be greatly appreciated.

Thank you!

[prime5711]

I am also testing the VD66GY camera module,
and I find this issue puzzling.
Based on the "Embedded Functions" section of the VD66GY datasheet,
I had expected much better image quality than what I am seeing.

I am wondering if the cause of this issue is a missing configuration in the kernel device driver,
or if the image quality is simply poor even with proper settings—implying that an external ISP is required.

Additionally, I used the "STEVAL-CAM-M0I1" to test the VD66GY,
but because the MIPI signal polarity is reversed, a direct connection isn't possible, requiring the fabrication of an interface board.
- There seem to be very few boards with an RPI camera interface that support MIPI polarity reversal, and the process is cumbersome.