By Mark Watts
I recently watched a documentary on Ansel Adams. I have always been a great admirer of his work. His ability to capture such detail and beauty in black-and-white photographs has a very strong appeal to me.
“You do not take a photograph, you make it,” Ansel Adam said.
Adams broke the imaging process down into separate components – composition, negative and print.
Composition
First was the “Visualization.” The creating of the final image in his mind’s eye. To understand the composition and purpose of the image before the creation is the same process used in medical imaging. Why do we need the image? Does it answer a differential diagnosis question or affirm a probability calculation of a diagnose?
Negative
The next set for Adams was more mechanical – lens selection, filters and glass plate negative selection.
For imaging, it is modality selection, exams selection and image capture.
Adams invented a system to grade out the range of black to white gradient on his photo prints. This “Zone system of light for photography” assigns a number value of “0” to black and for every f stop on the camera, change from dark to light on the grey scale, 1, 2, 3 … until you reach white which is defined as 10.
The first digital imaging in computed tomography were added by the use of Hounsfield units. The Hounsfield unit is a dimensionless unit universally used in CT scanning to express CT numbers in a standardized and convenient form. Hounsfield units are obtained from a linear transformation of the measured attenuation coefficients. This transformation is based on the arbitrarily assigned densities of air and pure water:
Radiodensity of distilled water at standard temperature and pressure (STP) = 0 HU
Radiodensity of air at STP = -1000 HU
Both systems give the human eye the ability to perceive minute details.
This is where the true artistry of Adams and radiologists come in to play.
Adams would use darkroom techniques to block or focus light on the photographic printed paper.
Not based on what was on the negative, but to match the image in his mind’s eye at the beginning of the process.
A radiologist takes the medical image and applies his past experiences and training to also interpret it to produce a final product – a report.
Can you use modern technology to generate an Ansel Adams masterpiece?
Can artificial intelligence give a final report that is a masterpiece?
Photoshop has an Ansel Adams type program built in to emulate the Zone system. This process changes the balance of the whole picture simultaneously. Washing out subtle features
Artificial imaging can describe the patterns and recognize the pixels. The patient deserves the thoughtful product of true artists that is not generalized or homogenized. Over reading or under reporting are sins of mass production. Good enough for an engineer is not good enough for our patients.
A report that not just describes the image but applies an N of 1 masterpiece of intent.
“Art is the affirmation of life,” said Adams.
The best outcome is when art and science work together.
Mark Watts is an experienced imaging professional who founded an AI company called Zenlike.ai.
