Saturday, 6 February 2016

Gestalt - Using Colour To Help Describe Angles

Gestalt is all about size, structure and movement.  In analytical terms at the atomic level this all comes down to an analysis of measurement and angles.  My early postings on the subject of gestalt have highlighted the problem of accurate measurement from photographs.  In bird identification we talk about proportion all the time.  However, whether for example it's Primary Projection, Bill To Eye Ratio or Leg Proportion Analysis there are limits to how accurately we can take measurements from two-dimensional photographs, as the postings in each of these links help to explain.  

In reality, as with judging proportion by eye without the aid of an accurate ruler or guide, when we discuss these ratios from photographs we are basing our analysis on subjective approximations, not on sound measurement.  Sometimes that is good enough for our needs.  While watching a bird over a period of time or analysing a bird based on numerous images, it is possible to form a fairly good and very often a very accurate impression about the relative proportion of things.  I want to apply this type of fuzzy logic in another way here.  

If you have read much of this blog you will have noticed that I like to use visual tools to draw out and present detail from an image for presentation purposes or to help clarify analytical observations and opinions.  What if there was a useful tool that would allow someone to present the approximate angles of lines within images.  When we analyse images, mentally we are often thinking about angles and perspective but when we go on to describe those things we rarely try to quantify what we mean.  Me might say for instance that the bird appears to be slightly facing the camera or that the bird's body is tilted slightly away from us in flight as it banks.  Wouldn't it be nice to have a standard tool that we could use to present our analysis of these subtle angles within an image in a way that others can appreciate more clearly and therefore discuss and critique.  Here is such a tool.

So, its basically a colour wheel or pie-chart.  When assessing angles in an image the only stipulation would be to specify that the tool is being used in a horizontal or vertical plane.  Taking the image of the Northern Wheatear Oenanthe oenanthe here is my appreciation of some of the angles in the horizontal plane.  

Someone else looking at this same Wheatear image might say, "the head looks like it is tilted away from the camera at the same angle as the wing".  That may be correct and my analysis may be wrong.  Thus the debate begins.  This form of analysis is intended to generate clarity and consensus around these subtle distinctions, or at the very least to thrash out the challenges with an identification where matters like size, proportion and lighting play a key role in the identification.  

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