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Morgane-des-Ligneris
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It is a long article, I will try to go through it quickly tomorrow, so please let me know if some parts should be simplified. Thank you.

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Interesting article ! Could be a little bit more synthetic but I'm sure your presentation will be.
I'm now wondering what is the fundamental difference between distance-heatmaps as presented here and level sets, I feel like level sets already include a distance to the point of interest ? As here the heatmaps are built based on level-sets.
Great review

&= \int_C w(x - y) dy
\end{align*}$$

To be faster than while using a numerical integration and to generalize the description, $$H(x)$$ is simlified. They make the assumption that $$w(x)$$ is symetric $$w(x) = w(y)$$ for all $$\vert \vert x \vert \vert \underset{2}{} = \vert \vert y \vert \vert \underset{2}{}$$.
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than what ?

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than when using a numerical integration

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@nathanpainchaud nathanpainchaud Nov 9, 2023

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I think the phrasing can lead to some confusion (I had the same initial reaction as Nicolas), so I would suggest maybe something like (+ a fix to a typo in simplified and symmetric 😉):

Suggested change
To be faster than while using a numerical integration and to generalize the description, $$H(x)$$ is simlified. They make the assumption that $$w(x)$$ is symetric $$w(x) = w(y)$$ for all $$\vert \vert x \vert \vert \underset{2}{} = \vert \vert y \vert \vert \underset{2}{}$$.
$$H(x)$$ is simplified to i) be faster than when using a numerical integration, and ii) to generalize the description. They make the assumption that $$w(x)$$ is symmetric $$w(x) = w(y)$$ for all $$\vert \vert x \vert \vert \underset{2}{} = \vert \vert y \vert \vert \underset{2}{}$$.


If $$C$$ is an infinite straight line, the evaluation of the integral simplifies to $$h : \mathbb{R} \rightarrow \mathbb{R}$$ which only depends on the distance to the line C :

$$(4) \quad H(x)= h(f(x))$$
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I'm not so sure what is h(.) as it has not been defined before

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just above "the evaluation of the integral simplifies to h"


## Numerical approximation and implementation

![](/collections/images/elongated_structures/fig_2.jpg)
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I think this image could be bigger

- **calculate distance value for each spatial position inside** : distance from the spatial position to the original curve
- **heatmap calculation** : resolve multiple distance estimates from overlapping bounding boxes then evaluate the distance values with the distance dependent function.

**Curve parameterization**
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Is this the following of the previous list ? If not maybe it would be clearer to add a small sentence to indicate what is going on

- Minimum distance : only the estimator with the smallest point-to-line distance is used for evaluating the distance-dependent function. Easily parallelized, it allows the heatmap generation algorithm to be executed at linear time complexity
- Inverse distance weighting (IDW) : allows the contribution of all distance estimates.

**Selection of the distance-dependant function**
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is this h ?

## CNN-based estimation error for different signal and heatmap configurations
Signal simulation model and ASSD metric to assess the accuracy of these approximations (*Simulated signals of chest X-ray, 2D experiment)

![](/collections/images/elongated_structures/fig_5.jpg)
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could be bigger

- the custom catheter signal is estimated with minimal error across heatmap configuration
- strength of the signal has minimal impact

*The influence of signal and heatmap width*
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I think you might be using bullet lists too much, not doing lists forces you to be more synthetic I think


## Application to 2D and 3D representation problems
---
## Anatomiacal structure detection on knee radiographs (2D experiment)
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anatomical


D relies on the global orientation of the bone ⇒ contextual anatomical structure

![](/collections/images/elongated_structures/fig_6.jpg)
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bigger figures please


*Perspectives*
- it would be helpful to separate structures into separate output channels (even if they can’t be matched between different images of volumes)
- using a neural network to approximate knots and B-spline curve approximation parameters for signal reconstruction is a promising idea
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I'm surprised I didn't see the word "knot" before

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A couple of typos + phrasing suggestions 😉

cite:
authors: "Kordon, F., Stiglmayr, M., Maier, A. et al. "
title: "A principled representation of elongated structures using heatmaps"
venue: "Nature, sientific reports"
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Capitalization + small typo 😉

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venue: "Nature, sientific reports"
venue: "Nature, Scientific Reports"

- Create a target function that CNN can well aproximate
- Convert the curve into a heatmap through a convolution with a filter function
- Linear time complexity
- Applicalble to various surgical 2D and 3D data task
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Typo:

Suggested change
- Applicalble to various surgical 2D and 3D data task
- Applicable to various surgical 2D and 3D data task

&= \int_C w(x - y) dy
\end{align*}$$

To be faster than while using a numerical integration and to generalize the description, $$H(x)$$ is simlified. They make the assumption that $$w(x)$$ is symetric $$w(x) = w(y)$$ for all $$\vert \vert x \vert \vert \underset{2}{} = \vert \vert y \vert \vert \underset{2}{}$$.
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@nathanpainchaud nathanpainchaud Nov 9, 2023

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I think the phrasing can lead to some confusion (I had the same initial reaction as Nicolas), so I would suggest maybe something like (+ a fix to a typo in simplified and symmetric 😉):

Suggested change
To be faster than while using a numerical integration and to generalize the description, $$H(x)$$ is simlified. They make the assumption that $$w(x)$$ is symetric $$w(x) = w(y)$$ for all $$\vert \vert x \vert \vert \underset{2}{} = \vert \vert y \vert \vert \underset{2}{}$$.
$$H(x)$$ is simplified to i) be faster than when using a numerical integration, and ii) to generalize the description. They make the assumption that $$w(x)$$ is symmetric $$w(x) = w(y)$$ for all $$\vert \vert x \vert \vert \underset{2}{} = \vert \vert y \vert \vert \underset{2}{}$$.

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