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How it works . . .

  • Shotgun-Insight is a shotgun pellet recognition and shotgun pattern analysis programme.

  • To analyse a pattern . . . (sample pattern here)

    • Shoot at a plain white paper/card target on a pattern plate. The target or distance should be such that all the shot holes are captured. Shotgun-Insight can simulate different distances so there is no need to shoot from 75yds to estimate what the long distance pattern is!

    • Take a digital photograph of the target, download to a PC as a JPEG file.
      Load the image into Shotgun-Insight . . .

    • Use automatic and manual controls to identify pellet marks, the scale of the target and point of aim.

    • Shotgun-Insight generates the graphical and numerical reports.







Actual screen shot of Shotgun-Insight working with a real target . . .


Image manipulation and pellet recognition controls . . . .

Decrease / increase the size of the image. Does not affect pellet detection.


Block a small, medium or large area of the image from automatic pellet detection. (Manually added pellets are unaffected.)

Set active area button. Drag the boxes at the top-left and bottom-right to set the area that will be scanned for pellet holes.


Adjust the slider to set the automatic pellet detection level. If the contrast between the pellet marks and background is poor false detection is likely. See above for blocking erroneous pellet detection.

Set the scale of the image. Drag the up/down arrows on the image to indicate a known vertical distance on the image and the left/right arrows to indicate a known horizontal distance. Move the graticule to indicate the point of aim.


"double" is used to detect near-coincident pellet strikes. (NB this feature works best with larger pellets that give a well defined and consistent impact mark. "size" ignores features much larger than the typical pellet size. If a conventional pattern plate target with a bulls-eye and pre-marked segments is scanned-in, the "size" setting can suppress these features of the target.

Manually add or delete single pellets. Clicking will add a 'manual' pellet - shown as a blue marker. SHIFT+clicking over a manually generated pellet mark will delete it. SHIFT+click over an automatically generated pellet mark will exclude the pellet from the analysis.

Horizontal / Vertical fields to enter the true distance indicated by the scale setting arrows (see above).


Update the analysis panel with the latest status of the image.


The distances may be input in imperial inches or metric cm. However, all outputs are displayed in inches and graphical output is shown with respect to a 30" and 20" circle.



Material for the target: It must be strong enough to withstand pellet "bounce-back" from the pattern plate and being struck by the wad. Wallpaper is easy to find and can be quite low-cost. 2-pieces taped together giving an area approximately 40" x 40" work well. Further, stippled or waffle finish provides some thickness to the paper so the pellets make clearer holes - a halfway house between paper and cardboard (the textured side faces the pattern plate, the smooth back of the paper is the target side!!). One can use pre-marked targets showing circles / segments as sold by a number of ammunition manufacturers. However, one has to help-out the software by identifying the pellet holes that fall on the pre-marked features (it's hard for the image recognition algorithm to pick-out a dark hole on a black line!). Normal office type paper will tear. Some things which should help - a target dispenser 'Targomatic' and a role of 'Shotgun Patterning Material' or some heavy-weight art paper available on long rolls and at low cost!


Taping the target together: If one needs to join two pieces of paper together, do not use 'Scotchtape' / 'Sellotape' on the front face because it is shiny and reflects back the flash of the camera! Draughting / masking tape is ideal.


Camera: Shotgun-Insight was developed with a medium/low cost Nikon Coolpix 2 mega-pixels camera. Higher resolution requires a faster computer to process the data. Anything a lot less will have difficulty to pick-out No.8 / No.9 shot. When taking a picture make sure that the camera is square-on to the target to minimise distortion. The software can correct for small rotational errors.


Computer: Consider a 700MHz Pentium III with 256MB RAM as the minimum for ~2M pixel pictures. 


(c) Dr A C Jones