[libcamera-devel] [PATCH v3 5/5] libcamera: ipa: raspberrypi: ALSC: Handle user transform

[Laurent Pinchart]

Hi David,

Thank you for the patch.

On Fri, Aug 21, 2020 at 04:56:41PM +0100, David Plowman wrote:
> Update ALSC (Auto Lens Shading Correction) to handle correctly the
> user transform now passed in the camera mode.
> 
> The user transform is applied directly in the sensor so the image
> statistics already incorporate it, and the adaptive algorithm is
> entirely agnostic towards it, so all we have to do is flip the
> calibrated tables to match. (These tables will have been calibrated
> without the user transform.)
> 
> Signed-off-by: David Plowman <david.plowman at raspberrypi.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> ---
>  src/ipa/raspberrypi/controller/rpi/alsc.cpp | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/src/ipa/raspberrypi/controller/rpi/alsc.cpp b/src/ipa/raspberrypi/controller/rpi/alsc.cpp
> index 9df713a..fdeda21 100644
> --- a/src/ipa/raspberrypi/controller/rpi/alsc.cpp
> +++ b/src/ipa/raspberrypi/controller/rpi/alsc.cpp
> @@ -184,7 +184,10 @@ void Alsc::waitForAysncThread()
>  
>  static bool compare_modes(CameraMode const &cm0, CameraMode const &cm1)
>  {
> -	// Return true if the modes crop from the sensor significantly differently.
> +	// Return true if the modes crop from the sensor significantly differently,
> +	// or if the user transform has changed.
> +	if (cm0.transform != cm1.transform)
> +		return true;
>  	int left_diff = abs(cm0.crop_x - cm1.crop_x);
>  	int top_diff = abs(cm0.crop_y - cm1.crop_y);
>  	int right_diff = fabs(cm0.crop_x + cm0.scale_x * cm0.width -
> @@ -429,6 +432,10 @@ void resample_cal_table(double const cal_table_in[XY],
>  		xf[i] = x - x_lo[i];
>  		x_hi[i] = std::min(x_lo[i] + 1, X - 1);
>  		x_lo[i] = std::max(x_lo[i], 0);
> +		if (!!(camera_mode.transform & libcamera::Transform::HFlip)) {
> +			x_lo[i] = X - 1 - x_lo[i];
> +			x_hi[i] = X - 1 - x_hi[i];
> +		}
>  	}
>  	// Now march over the output table generating the new values.
>  	double scale_y = camera_mode.sensor_height /
> @@ -441,6 +448,10 @@ void resample_cal_table(double const cal_table_in[XY],
>  		double yf = y - y_lo;
>  		int y_hi = std::min(y_lo + 1, Y - 1);
>  		y_lo = std::max(y_lo, 0);
> +		if (!!(camera_mode.transform & libcamera::Transform::VFlip)) {
> +			y_lo = Y - 1 - y_lo;
> +			y_hi = Y - 1 - y_hi;
> +		}
>  		double const *row_above = cal_table_in + X * y_lo;
>  		double const *row_below = cal_table_in + X * y_hi;
>  		for (int i = 0; i < X; i++) {

-- 
Regards,

Laurent Pinchart