Saturday 27 September 2014

Image Quality Tool - Initial Analysis

Now that I have completed my initial research around the key image quality parameters and put up some of my findings on the blog, it is time to put the Image Quality Tool through some tests.  Before that I would like to summarise some of the initial analysis I have been doing.

Fool the Tool

In an early posting (HERE) I started to question ways in which the controls put in place by the tool might be intentionally bypassed in order to fool the scoring.  One for example might quite easily re-size and image larger in order to bring up the resolution scoring in the tool, thus possibly moving a low resolution, poor quality image up a quality notch or two, without having actually improved the image quality.  This got me a little concerned so I gave some further thought to the various other ways in which images might be manipulated to fool the tool.  I summarised these in the video below.

My overall conclusions were that, provided image modification improved the quality of the image, the effects were generally positive.  It is of course possible to make a dog's dinner out of any image photofinishing attempt, especially if someone saves a bad attempt and loses some vital data in the process.  All these tools need to be used correctly and sparingly and care must be taken not to lose the original file data.  

In the next posting I am going to be testing the image scoring using a number of bird images of varying quality.  Out of interest, I will be taking an image produced by the camera without modification and comparing it with one in which I have have attempted to improve the image quality for identification purposes (modified from JPEG, not RAW).  It will be interesting to see how the scoring is affected and whether or not there is a link between an improved quality score and any genuine improvement in the ability to discern useful additional ID features from a modified image. 

Scoring Logic

As a result of some of my initial analysis I have brought the scoring logic on a bit from my original draft and it currently looks like this.  

Clearly, some parameters have been weighted quite differently to others.  Some score heavily above the line and others below the line.  This may need a bit more tweaking to get it just right.

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