[libcamera-devel] [PATCH] utils: raspberrypi: ctt: Improve the Macbeth Chart search reliability

[Kieran Bingham]

Quoting David Plowman via libcamera-devel (2023-12-01 11:07:53)
> Previously the code would brighten up images in case the Macbeth Chart
> is slightly dark, and also zoom in on sections of it to look for
> charts occupying less of the field of view. But it would not do both
> together.
> 
> This change makes the search for smaller charts also repeat that
> search for the brightened up images that it made earlier, thereby
> increasing the chances of success for non-optimal tuning images.
> 
> There are also a couple of very small drive-by typo fixes.
> 
> Signed-off-by: David Plowman <david.plowman at raspberrypi.com>


Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

And also I believe:

Tested-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

> ---
>  utils/raspberrypi/ctt/ctt_macbeth_locator.py | 69 ++++++++++++--------
>  1 file changed, 40 insertions(+), 29 deletions(-)
> 
> diff --git a/utils/raspberrypi/ctt/ctt_macbeth_locator.py b/utils/raspberrypi/ctt/ctt_macbeth_locator.py
> index 3e95df89..178aeed0 100644
> --- a/utils/raspberrypi/ctt/ctt_macbeth_locator.py
> +++ b/utils/raspberrypi/ctt/ctt_macbeth_locator.py
> @@ -57,6 +57,10 @@ def find_macbeth(Cam, img, mac_config=(0, 0)):
>      """
>      cor, mac, coords, msg = get_macbeth_chart(img, ref_data)
>  
> +    # Keep a list that will include this and any brightened up versions of
> +    # the image for reuse.
> +    all_images = [img]
> +
>      """
>      following bits of code tries to fix common problems with simple
>      techniques.
> @@ -71,6 +75,7 @@ def find_macbeth(Cam, img, mac_config=(0, 0)):
>      if cor < 0.75:
>          a = 2
>          img_br = cv2.convertScaleAbs(img, alpha=a, beta=0)
> +        all_images.append(img_br)
>          cor_b, mac_b, coords_b, msg_b = get_macbeth_chart(img_br, ref_data)
>          if cor_b > cor:
>              cor, mac, coords, msg = cor_b, mac_b, coords_b, msg_b
> @@ -81,6 +86,7 @@ def find_macbeth(Cam, img, mac_config=(0, 0)):
>      if cor < 0.75:
>          a = 4
>          img_br = cv2.convertScaleAbs(img, alpha=a, beta=0)
> +        all_images.append(img_br)
>          cor_b, mac_b, coords_b, msg_b = get_macbeth_chart(img_br, ref_data)
>          if cor_b > cor:
>              cor, mac, coords, msg = cor_b, mac_b, coords_b, msg_b
> @@ -128,23 +134,26 @@ def find_macbeth(Cam, img, mac_config=(0, 0)):
>          h_inc = int(h/6)
>          """
>          for each subselection, look for a macbeth chart
> +        loop over this and any brightened up images that we made to increase the
> +        likelihood of success
>          """
> -        for i in range(3):
> -            for j in range(3):
> -                w_s, h_s = i*w_inc, j*h_inc
> -                img_sel = img[w_s:w_s+w_sel, h_s:h_s+h_sel]
> -                cor_ij, mac_ij, coords_ij, msg_ij = get_macbeth_chart(img_sel, ref_data)
> -                """
> -                if the correlation is better than the best then record the
> -                scale and current subselection at which macbeth chart was
> -                found. Also record the coordinates, macbeth chart and message.
> -                """
> -                if cor_ij > cor:
> -                    cor = cor_ij
> -                    mac, coords, msg = mac_ij, coords_ij, msg_ij
> -                    ii, jj = i, j
> -                    w_best, h_best = w_inc, h_inc
> -                    d_best = 1
> +        for img_br in all_images:
> +            for i in range(3):
> +                for j in range(3):
> +                    w_s, h_s = i*w_inc, j*h_inc
> +                    img_sel = img_br[w_s:w_s+w_sel, h_s:h_s+h_sel]
> +                    cor_ij, mac_ij, coords_ij, msg_ij = get_macbeth_chart(img_sel, ref_data)
> +                    """
> +                    if the correlation is better than the best then record the
> +                    scale and current subselection at which macbeth chart was
> +                    found. Also record the coordinates, macbeth chart and message.
> +                    """
> +                    if cor_ij > cor:
> +                        cor = cor_ij
> +                        mac, coords, msg = mac_ij, coords_ij, msg_ij
> +                        ii, jj = i, j
> +                        w_best, h_best = w_inc, h_inc
> +                        d_best = 1
>  
>      """
>      scale 2
> @@ -157,17 +166,19 @@ def find_macbeth(Cam, img, mac_config=(0, 0)):
>          h_sel = int(h/2)
>          w_inc = int(w/8)
>          h_inc = int(h/8)
> -        for i in range(5):
> -            for j in range(5):
> -                w_s, h_s = i*w_inc, j*h_inc
> -                img_sel = img[w_s:w_s+w_sel, h_s:h_s+h_sel]
> -                cor_ij, mac_ij, coords_ij, msg_ij = get_macbeth_chart(img_sel, ref_data)
> -                if cor_ij > cor:
> -                    cor = cor_ij
> -                    mac, coords, msg = mac_ij, coords_ij, msg_ij
> -                    ii, jj = i, j
> -                    w_best, h_best = w_inc, h_inc
> -                    d_best = 2
> +        # Again, loop over any brightened up images as well
> +        for img_br in all_images:
> +            for i in range(5):
> +                for j in range(5):
> +                    w_s, h_s = i*w_inc, j*h_inc
> +                    img_sel = img_br[w_s:w_s+w_sel, h_s:h_s+h_sel]
> +                    cor_ij, mac_ij, coords_ij, msg_ij = get_macbeth_chart(img_sel, ref_data)
> +                    if cor_ij > cor:
> +                        cor = cor_ij
> +                        mac, coords, msg = mac_ij, coords_ij, msg_ij
> +                        ii, jj = i, j
> +                        w_best, h_best = w_inc, h_inc
> +                        d_best = 2
>  
>      """
>      The following code checks for macbeth charts at even smaller scales. This
> @@ -238,7 +249,7 @@ def find_macbeth(Cam, img, mac_config=(0, 0)):
>      print error or success message
>      """
>      print(msg)
> -    Cam.log += '\n' + msg
> +    Cam.log += '\n' + str(msg)
>      if msg == success_msg:
>          coords_fit = coords
>          Cam.log += '\nMacbeth chart vertices:\n'
> @@ -606,7 +617,7 @@ def get_macbeth_chart(img, ref_data):
>                      '\nNot enough squares found'
>                      '\nPossible problems:\n'
>                      '- Macbeth chart is occluded\n'
> -                    '- Macbeth chart is too dark of bright\n'
> +                    '- Macbeth chart is too dark or bright\n'
>                  )
>  
>              ref_cents = np.array(ref_cents)
> -- 
> 2.34.1
>