Hello everyone,
Does anyone know about any package for image processing, for example, to calculate body mass index pased on a picture, silouette or image. Any guidance will be greatly appreciated. Best regards, Paul [[alternative HTML version deleted]] ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
1) doing a web search on:
"R package to calculate body mass index based on a picture, silhouette or image" did *not* bring up any R packages, but did provide what looked like relevant links to other software and research/discussions. You can decide whether or not this is useful "guidance" (if you have not already done this). Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Sun, Feb 28, 2021 at 8:39 AM Paul Bernal <[hidden email]> wrote: > Hello everyone, > > Does anyone know about any package for image processing, for example, to > calculate body mass index pased on a picture, silouette or image. > > Any guidance will be greatly appreciated. > > Best regards, > > Paul > > [[alternative HTML version deleted]] > > ______________________________________________ > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
In reply to this post by PaulJr
Hi Paul,
The paper doesn't seem to mention R and the journal doesn't inspire confidence, but the formulas provided give you a start: https://www.researchgate.net/publication/280133090_Calculation_of_Body_Mass_Index_using_Image_Processing_Techniques Jim On Mon, Mar 1, 2021 at 3:39 AM Paul Bernal <[hidden email]> wrote: > > Hello everyone, > > Does anyone know about any package for image processing, for example, to > calculate body mass index pased on a picture, silouette or image. > > Any guidance will be greatly appreciated. > > Best regards, > > Paul > > [[alternative HTML version deleted]] > > ______________________________________________ > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
In reply to this post by PaulJr
Hello Paul Bernal,
(sorry, forgot to CC) Re: > Does anyone know about any package for image processing, for example, to > calculate body mass index pased on a picture, silouette or image. This sounds more like a job for the image analysis program NIH Image (the Java-version "ImageJ" being available for most platforms). ImageJ was designed for the analysis of microscopic images of cells etcetera, and can count, mark and measure objects. However, it works for 2D images unless jou have a stack of images. For R there is a Package ‘EBImage’ for image manipulation and measuring that might also be interesting (but also 2D I guess). Succes and Best regards, Franklin ----------- Franklin Bretschneider Dept of Biology Utrecht University [hidden email] [hidden email] Franklin Bretschneider Dept of Biology Utrecht University [hidden email] ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
In reply to this post by PaulJr
Hi Paul,
If the background is relatively uniform: Then a simple algorithm could be used, to distinguish foreground from background points. Essentially, returning a logical matrix. Otherwise, I'm assuming that suitable pooling/convolution operations could be used for this purpose. Then you could estimate *relative* measures of height and mass from the logical matrix. (With more precise measures being possible, if you know the image scales). There are a number of R packages for reading images. Currently, I mainly use Simon Urbanek's package, "png". I'm currently creating a package with support for pooling/convolution operations, and related utility functions. However, it's not ready yet. Another option is Jeroen Ooms' package, "magick". best, B. On Mon, Mar 1, 2021 at 5:39 AM Paul Bernal <[hidden email]> wrote: > > Hello everyone, > > Does anyone know about any package for image processing, for example, to > calculate body mass index pased on a picture, silouette or image. > > Any guidance will be greatly appreciated. > > Best regards, > > Paul > > [[alternative HTML version deleted]] > > ______________________________________________ > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
In reply to this post by PaulJr
"Body Mass Index" is a rather bizarre thing:
body.mass.in.kg / height.in.m^2 I have never been able to find any biological or physical meaning for this. Yet clinicians are solemnly advised to measure the weight to the nearest 0.1kg and the height to the nearest 0.1cm. How do you propose to determine the weight from a single image? Even an R package cannot perform magic. On Mon, 1 Mar 2021 at 05:39, Paul Bernal <[hidden email]> wrote: > Hello everyone, > > Does anyone know about any package for image processing, for example, to > calculate body mass index pased on a picture, silouette or image. > > Any guidance will be greatly appreciated. > > Best regards, > > Paul > > [[alternative HTML version deleted]] > > ______________________________________________ > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
In reply to this post by PaulJr
"Body Mass Index" is a rather bizarre thing:body.mass.in.kg / height.in.m^2I have never been able to find any biologicalor physical meaning for this. Yet cliniciansare solemnly advised to measure the weight tothe nearest 0.1kg and the height to thenearest 0.1cm.How do you propose to determine the weight froma single image? Even an R package cannot perform magic.On Mon, 1 Mar 2021 at 05:39, Paul Bernal <[hidden email]> <mailto:[hidden email]> wrote:
> Hello everyone,Does anyone know about any package for image processing, for example, tocalculate body mass index pased on a picture, silouette or image.Any guidance will be greatly appreciated.Best regards,Paul > A quick search with the terms "BMI flawed" produces an enormous list of hits pointing out the problems with BMI as an index. Here's one from a dozen or so years ago: https://www.npr.org/templates/story/story.php?storyId=106268439 And a quote from that piece: "The BMI was introduced in the early 19th century by a Belgian named Lambert Adolphe Jacques Quetelet. He was a mathematician, not a physician. He produced the formula to give a quick and easy way to measure the degree of obesity of the general population to assist the government in allocating resources. In other words, it is a 200-year-old hack." As an index of obesity in individuals, BMI has some glaring flaws. - T. Arthur Milne ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
In reply to this post by Richard O'Keefe-2
I must agree with the criticism of BMI as a diagnostic index. It is
easy to tell if a person is - ahem - wide and not very high with a single glance. These elementary parameters can easily be deduced from an image of said person. However, it does not convey that essential ratio of muscle to - ahem - adipose tissue that is the stated reason for its prominence. I suggest an older, but more valid, index that was used in the identification of witches. Simply tie the person's hands behind their back and throw him or her into the deep end of the pool. Time to drowning is the response variable and I am certain that those now chastised for their adipose tissue will vastly prefer it. Jim On Mon, Mar 1, 2021 at 10:24 PM Richard O'Keefe <[hidden email]> wrote: > > "Body Mass Index" is a rather bizarre thing: > body.mass.in.kg / height.in.m^2 > I have never been able to find any biological > or physical meaning for this. Yet clinicians > are solemnly advised to measure the weight to > the nearest 0.1kg and the height to the > nearest 0.1cm. > > How do you propose to determine the weight from > a single image? Even an R package cannot perform magic. > > > On Mon, 1 Mar 2021 at 05:39, Paul Bernal <[hidden email]> wrote: > > > Hello everyone, > > > > Does anyone know about any package for image processing, for example, to > > calculate body mass index pased on a picture, silouette or image. > > > > Any guidance will be greatly appreciated. > > > > Best regards, > > > > Paul > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide > > http://www.R-project.org/posting-guide.html > > and provide commented, minimal, self-contained, reproducible code. > > > > [[alternative HTML version deleted]] > > ______________________________________________ > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
Colleagues,
BMI has is failures, but it has demonstrated utility. BMI predicts multiple outcome measures including cardiovascular disease and mortality. Don't through out a useful metric because it is not the perfect metric. As to why BMI is computed as weight/height^2, it can be shown that dividing height by the square of weight decreases the correlation between weight and height. The optimum exponent (i.e. the power that most effectively minimizes the correlation between weight and height) is not the same in men and women and it differs by race. In general an exponent of 2.0 is best for men; for women an exponent of 2.2 is a bit better than 2.0. In any event, don't let the perfect get in the way of the good. John John David Sorkin M.D., Ph.D. Professor of Medicine Chief, Biostatistics and Informatics University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine Baltimore VA Medical Center 10 North Greene Street GRECC (BT/18/GR) Baltimore, MD 21201-1524 (Phone) 410-605-7119 (Fax) 410-605-7913 (Please call phone number above prior to faxing) ________________________________________ From: R-help <[hidden email]> on behalf of Jim Lemon <[hidden email]> Sent: Monday, March 1, 2021 4:23 PM To: Richard O'Keefe; r-help mailing list Subject: Re: [R] Image processing in R for BMI calculation I must agree with the criticism of BMI as a diagnostic index. It is easy to tell if a person is - ahem - wide and not very high with a single glance. These elementary parameters can easily be deduced from an image of said person. However, it does not convey that essential ratio of muscle to - ahem - adipose tissue that is the stated reason for its prominence. I suggest an older, but more valid, index that was used in the identification of witches. Simply tie the person's hands behind their back and throw him or her into the deep end of the pool. Time to drowning is the response variable and I am certain that those now chastised for their adipose tissue will vastly prefer it. Jim On Mon, Mar 1, 2021 at 10:24 PM Richard O'Keefe <[hidden email]> wrote: > > "Body Mass Index" is a rather bizarre thing: > body.mass.in.kg / height.in.m^2 > I have never been able to find any biological > or physical meaning for this. Yet clinicians > are solemnly advised to measure the weight to > the nearest 0.1kg and the height to the > nearest 0.1cm. > > How do you propose to determine the weight from > a single image? Even an R package cannot perform magic. > > > On Mon, 1 Mar 2021 at 05:39, Paul Bernal <[hidden email]> wrote: > > > Hello everyone, > > > > Does anyone know about any package for image processing, for example, to > > calculate body mass index pased on a picture, silouette or image. > > > > Any guidance will be greatly appreciated. > > > > Best regards, > > > > Paul > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432633266%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=h%2FZ9zAI4aad5GEtvB1H9BoN4bxRYnATV%2Fds7r8D2s04%3D&reserved=0 > > PLEASE do read the posting guide > > https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.r-project.org%2Fposting-guide.html&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432633266%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=2IvMsdifWeGaAyBNT%2F7695rmNX6O1Pb3G90%2FlrpU0KA%3D&reserved=0 > > and provide commented, minimal, self-contained, reproducible code. > > > > [[alternative HTML version deleted]] > > ______________________________________________ > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432633266%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=h%2FZ9zAI4aad5GEtvB1H9BoN4bxRYnATV%2Fds7r8D2s04%3D&reserved=0 > PLEASE do read the posting guide https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.r-project.org%2Fposting-guide.html&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432643223%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Ht2zAvvZpRhQ%2FKwjJXEbPreJd2RleNgzjD%2FhdbXhQc0%3D&reserved=0 > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432643223%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=6hUDWapuTlwnbSWTupkoiE6b9%2FyYxZIxjkJitJRZNiE%3D&reserved=0 PLEASE do read the posting guide https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.r-project.org%2Fposting-guide.html&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432643223%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Ht2zAvvZpRhQ%2FKwjJXEbPreJd2RleNgzjD%2FhdbXhQc0%3D&reserved=0 and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
I can't help but feel that a discussion on the merit of BMI is a
digression, from the OP's question. In addition, to being of no relevance to "R Programming". In relation to Richard's technical comments: As per my previous post, it is possible to get *relative" measures. (Assuming the images are not on a standardized scale, which they could be). In relation to Jim's anatomical comments: An improved algorithm could evaluate a subject's body type. In addition to factoring in gender, ethnic characteristics and age. In any case, I don't see why image-based classification is any less worthwhile than conclusions based on timeseries plots and scatterplots... ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
In reply to this post by Sorkin, John
This discussion is completely offr topic here. Please take it elsewhere.
Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Mon, Mar 1, 2021 at 1:42 PM Sorkin, John <[hidden email]> wrote: > Colleagues, > > BMI has is failures, but it has demonstrated utility. BMI predicts > multiple outcome measures including cardiovascular disease and mortality. > Don't through out a useful metric because it is not the perfect metric. > > As to why BMI is computed as weight/height^2, it can be shown that > dividing height by the square of weight decreases the correlation between > weight and height. The optimum exponent (i.e. the power that most > effectively minimizes the correlation between weight and height) is not the > same in men and women and it differs by race. In general an exponent of 2.0 > is best for men; for women an exponent of 2.2 is a bit better than 2.0. > > In any event, don't let the perfect get in the way of the good. > > John > > > John David Sorkin M.D., Ph.D. > Professor of Medicine > Chief, Biostatistics and Informatics > University of Maryland School of Medicine Division of Gerontology and > Geriatric Medicine > Baltimore VA Medical Center > 10 North Greene Street > GRECC (BT/18/GR) > Baltimore, MD 21201-1524 > (Phone) 410-605-7119 > (Fax) 410-605-7913 (Please call phone number above prior to faxing) > > > > ________________________________________ > From: R-help <[hidden email]> on behalf of Jim Lemon < > [hidden email]> > Sent: Monday, March 1, 2021 4:23 PM > To: Richard O'Keefe; r-help mailing list > Subject: Re: [R] Image processing in R for BMI calculation > > I must agree with the criticism of BMI as a diagnostic index. It is > easy to tell if a person is - ahem - wide and not very high with a > single glance. These elementary parameters can easily be deduced from > an image of said person. However, it does not convey that essential > ratio of muscle to - ahem - adipose tissue that is the stated reason > for its prominence. I suggest an older, but more valid, index that was > used in the identification of witches. Simply tie the person's hands > behind their back and throw him or her into the deep end of the pool. > Time to drowning is the response variable and I am certain that those > now chastised for their adipose tissue will vastly prefer it. > > Jim > > On Mon, Mar 1, 2021 at 10:24 PM Richard O'Keefe <[hidden email]> wrote: > > > > "Body Mass Index" is a rather bizarre thing: > > body.mass.in.kg / height.in.m^2 > > I have never been able to find any biological > > or physical meaning for this. Yet clinicians > > are solemnly advised to measure the weight to > > the nearest 0.1kg and the height to the > > nearest 0.1cm. > > > > How do you propose to determine the weight from > > a single image? Even an R package cannot perform magic. > > > > > > On Mon, 1 Mar 2021 at 05:39, Paul Bernal <[hidden email]> wrote: > > > > > Hello everyone, > > > > > > Does anyone know about any package for image processing, for example, > to > > > calculate body mass index pased on a picture, silouette or image. > > > > > > Any guidance will be greatly appreciated. > > > > > > Best regards, > > > > > > Paul > > > > > > [[alternative HTML version deleted]] > > > > > > ______________________________________________ > > > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > > > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432633266%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=h%2FZ9zAI4aad5GEtvB1H9BoN4bxRYnATV%2Fds7r8D2s04%3D&reserved=0 > > > PLEASE do read the posting guide > > > > https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.r-project.org%2Fposting-guide.html&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432633266%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=2IvMsdifWeGaAyBNT%2F7695rmNX6O1Pb3G90%2FlrpU0KA%3D&reserved=0 > > > and provide commented, minimal, self-contained, reproducible code. > > > > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432633266%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=h%2FZ9zAI4aad5GEtvB1H9BoN4bxRYnATV%2Fds7r8D2s04%3D&reserved=0 > > PLEASE do read the posting guide > https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.r-project.org%2Fposting-guide.html&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432643223%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Ht2zAvvZpRhQ%2FKwjJXEbPreJd2RleNgzjD%2FhdbXhQc0%3D&reserved=0 > > and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432643223%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=6hUDWapuTlwnbSWTupkoiE6b9%2FyYxZIxjkJitJRZNiE%3D&reserved=0 > PLEASE do read the posting guide > https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.r-project.org%2Fposting-guide.html&data=04%7C01%7CJSorkin%40som.umaryland.edu%7C58f4e3f9226c4ac456cf08d8dcf8532e%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502306432643223%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Ht2zAvvZpRhQ%2FKwjJXEbPreJd2RleNgzjD%2FhdbXhQc0%3D&reserved=0 > and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > [hidden email] mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
In reply to this post by Sorkin, John
Heinz,
I can't tell you how much I appreciated your email. I firmly believe that the rules and norms of the R-help mailing list need to be respected and followed. Nevertheless, I feared that if the comments were left unquestioned people who are not familiar with BMI, its strengths weakness, and its history, might assume from the comments that the metric is worthless, and that all studies that have used it are by extension worthless. It is for this reason, and because I thought it important the people understand that the exponent of 2 in the denominator is not a arbitrary value, but rather a value with a reason that I replied. I hope that the larger list community will forgive the liberty I have taken with the listerver's norms. I also hope that none of the people who were part of the email chain were personally offended by my comments. John John David Sorkin M.D., Ph.D. Professor of Medicine Chief, Biostatistics and Informatics University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine Baltimore VA Medical Center 10 North Greene Street GRECC (BT/18/GR) Baltimore, MD 21201-1524 (Phone) 410-605-7119 (Fax) 410-605-7913 (Please call phone number above prior to faxing) ________________________________________ From: Heinz Tuechler <[hidden email]> Sent: Monday, March 1, 2021 6:26 PM To: Sorkin, John; Jim Lemon; Richard O'Keefe; T. A. Milne via R-help; Abby Spurdle Subject: Re: [R] Image processing in R for BMI calculation Dear All, since Bert Gunter correctly stated that the discussion is off topic, I answer to you only. In my view John and Abby made very reasonable comments, while particularly the link https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.npr.org%2Ftemplates%2Fstory%2Fstory.php%3FstoryId%3D106268439&data=04%7C01%7Cjsorkin%40som.umaryland.edu%7Cd5d29291516a4b5c84d408d8dd096c00%7C717009a620de461a88940312a395cac9%7C0%7C0%7C637502379829397742%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=MKCnjEzFyRmCrO6Efxo0s%2BTJ4cV%2B3m1FPy61MPwptE8%3D&reserved=0 mentioned in the note of T. Arthur Milne seems remarkably superficial - maybe it's just a joke? Some examples: "Moreover, it ignores waist size, which is a clear indicator of obesity level." Without reference to hip? "Because the majority of people today (and in Quetelet's time) lead fairly sedentary lives ..." 200 years ago? "Because the BMI is a single number between 1 and 100 (like a percentage) ..." Try to imagine a BMI of 1, or of 100. The BMI will be between 1 and 100, but 1 to 100 will not be its range. "It suggests there are distinct categories of underweight, ideal, overweight and obese, with sharp boundaries that hinge on a decimal place." Why should categories be implied by the BMI itself? "It is embarrassing for one of the most scientifically, technologically and medicinally advanced nations in the world ..." That's true, at least for my eyes. When I visited the USA, I had the impression that in many cases you don't need a measure at all. best regards, Heinz Sorkin, John wrote/hat geschrieben on/am 01.03.2021 22:42: > Colleagues, > > BMI has is failures, but it has demonstrated utility. BMI predicts multiple outcome measures including cardiovascular disease and mortality. Don't through out a useful metric because it is not the perfect metric. > > As to why BMI is computed as weight/height^2, it can be shown that dividing height by the square of weight decreases the correlation between weight and height. The optimum exponent (i.e. the power that most effectively minimizes the correlation between weight and height) is not the same in men and women and it differs by race. In general an exponent of 2.0 is best for men; for women an exponent of 2.2 is a bit better than 2.0. > > In any event, don't let the perfect get in the way of the good. > > John > > > John David Sorkin M.D., Ph.D. > Professor of Medicine > Chief, Biostatistics and Informatics > University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine > Baltimore VA Medical Center > 10 North Greene Street > GRECC (BT/18/GR) > Baltimore, MD 21201-1524 > (Phone) 410-605-7119 > (Fax) 410-605-7913 (Please call phone number above prior to faxing) > > > > ________________________________________ > From: R-help <[hidden email]> on behalf of Jim Lemon <[hidden email]> > Sent: Monday, March 1, 2021 4:23 PM > To: Richard O'Keefe; r-help mailing list > Subject: Re: [R] Image processing in R for BMI calculation > > I must agree with the criticism of BMI as a diagnostic index. It is > easy to tell if a person is - ahem - wide and not very high with a > single glance. These elementary parameters can easily be deduced from > an image of said person. However, it does not convey that essential > ratio of muscle to - ahem - adipose tissue that is the stated reason > for its prominence. I suggest an older, but more valid, index that was > used in the identification of witches. Simply tie the person's hands > behind their back and throw him or her into the deep end of the pool. > Time to drowning is the response variable and I am certain that those > now chastised for their adipose tissue will vastly prefer it. > > Jim > > On Mon, Mar 1, 2021 at 10:24 PM Richard O'Keefe <[hidden email]> wrote: >> >> "Body Mass Index" is a rather bizarre thing: >> body.mass.in.kg / height.in.m^2 >> I have never been able to find any biological >> or physical meaning for this. Yet clinicians >> are solemnly advised to measure the weight to >> the nearest 0.1kg and the height to the >> nearest 0.1cm. >> >> How do you propose to determine the weight from >> a single image? Even an R package cannot perform magic. >> >> >> On Mon, 1 Mar 2021 at 05:39, Paul Bernal <[hidden email]> wrote: >> >>> Hello everyone, >>> >>> Does anyone know about any package for image processing, for example, to >>> calculate body mass index pased on a picture, silouette or image. >>> >>> Any guidance will be greatly appreciated. >>> >>> Best regards, >>> >>> Paul >>> ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. |
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