[libcamera-devel] [PATCH v2 02/11] utils: libtuning: modules: Add ALSC module

[Laurent Pinchart]

Hi Paul,

Thank you for the patch.

On Sat, Oct 22, 2022 at 03:23:01PM +0900, Paul Elder via libcamera-devel wrote:
> Add an ALSC module to libtuning's collection of modules. It is based on
> raspberrypi's ctt's ALSC, but customizable for different lens shading
> table sizes, among other things.

I think I would name the module LSC, not ALSC, as there's nothing
adaptative here.

> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> 
> ---
> Changes in v2:
> - fix python errors
> - fix style
> - add SPDX and copyright
> - don't call super().validateConfig()
> - fix sector splitting
>   - i forgot that we have to half the image size for each color channel
> - make the base ALSC module into an abstract module, which can be easily
>   used by other platforms to derive their own ALSC modules (see rkisp1's
>   module later in this series; i think it's quite nice)
> ---
>  .../tuning/libtuning/modules/alsc/__init__.py |  5 ++
>  utils/tuning/libtuning/modules/alsc/alsc.py   | 78 +++++++++++++++++++
>  2 files changed, 83 insertions(+)
>  create mode 100644 utils/tuning/libtuning/modules/alsc/__init__.py
>  create mode 100644 utils/tuning/libtuning/modules/alsc/alsc.py
> 
> diff --git a/utils/tuning/libtuning/modules/alsc/__init__.py b/utils/tuning/libtuning/modules/alsc/__init__.py
> new file mode 100644
> index 00000000..a8f28923
> --- /dev/null
> +++ b/utils/tuning/libtuning/modules/alsc/__init__.py
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +#
> +# Copyright (C) 2022, Paul Elder <paul.elder at ideasonboard.com>
> +
> +from libtuning.modules.alsc.alsc import ALSC
> diff --git a/utils/tuning/libtuning/modules/alsc/alsc.py b/utils/tuning/libtuning/modules/alsc/alsc.py
> new file mode 100644
> index 00000000..b708b28d
> --- /dev/null
> +++ b/utils/tuning/libtuning/modules/alsc/alsc.py
> @@ -0,0 +1,78 @@
> +# SPDX-License-Identifier: BSD-2-Clause
> +#
> +# Copyright (C) 2019, Raspberry Pi Ltd
> +# Copyright (C) 2022, Paul Elder <paul.elder at ideasonboard.com>
> +
> +from ..module import Module
> +
> +import libtuning as lt
> +import libtuning.utils as utils
> +
> +import numpy as np
> +
> +
> +class ALSC(Module):
> +    type = 'alsc'
> +    hr_name = 'ALSC (Base)'
> +    out_name = 'GenericALSC'
> +
> +    def __init__(self, *,
> +                 debug: list,
> +                 sector_shape: tuple,
> +                 sector_x_gradient: lt.Gradient,
> +                 sector_y_gradient: lt.Gradient,
> +                 sector_average_function: lt.Average,
> +                 smoothing_function: lt.Smoothing):
> +        super().__init__()
> +
> +        if (sector_x_gradient is lt.gradient.Linear and sector_x_remainder is None):

No need for parentheses. Same below.

> +            raise ValueError('sector_x_remainder must be specified if sector_x_gradient is Linear')

sector_x_remainder is not defined. Same for y. The "is
lt.gradient.Linear" test is always false, which is something you
probably want to fix too.

I assume all this will be revisited (I don't think that generic gradient
types will be useful), for now,

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

> +
> +        if (sector_y_gradient is lt.gradient.Linear and sector_y_remainder is None):
> +            raise ValueError('sector_y_remainder must be specified if sector_y_gradient is Linear')
> +
> +        self.debug = debug
> +
> +        self.sector_shape = sector_shape
> +        self.sector_x_gradient = sector_x_gradient
> +        self.sector_y_gradient = sector_y_gradient
> +        self.sector_average_function = sector_average_function
> +
> +        self.smoothing_function = smoothing_function
> +
> +    def _enumerate_alsc_images(self, images):
> +        for image in images:
> +            if image.alsc_only:
> +                yield image
> +
> +    def _get_grid(self, channel, img_w, img_h):
> +        # List of number of pixels in each sector
> +        sectors_x = self.sector_x_gradient.distribute(img_w / 2, self.sector_shape[0])
> +        sectors_y = self.sector_y_gradient.distribute(img_h / 2, self.sector_shape[1])
> +
> +        grid = []
> +
> +        r = 0
> +        for y in sectors_y:
> +            c = 0
> +            for x in sectors_x:
> +                grid.append(self.sector_average_function.average(channel[r:r + y, c:c + x]))
> +                c += x
> +            r += y
> +
> +        return np.array(grid)
> +
> +    def _lsc_single_channel(self, channel: np.array,
> +                            image: lt.Image, green_grid: np.array = None):
> +        grid = self._get_grid(channel, image.w, image.h)
> +        grid -= image.blacklevel_16
> +        if green_grid is None:
> +            table = np.reshape(1 / grid, self.sector_shape[::-1])
> +        else:
> +            table = np.reshape(green_grid / grid, self.sector_shape[::-1])
> +        table = self.smoothing_function.smoothing(table)
> +
> +        if green_grid is None:
> +            table = table / np.min(table)
> +
> +        return table, grid

-- 
Regards,

Laurent Pinchart