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True OMR Second Darkest Mark Detection For Erasure Analysis PowerPoint Presentation
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True OMR Second Darkest Mark Detection For Erasure Analysis. How Mark Sense Sees the World. Black and White only. No shades of gray. Loss of detail. Loss of accuracy when reading data. Mark Sense Black and White Image.

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Presentation Transcript
slide3

How Mark Sense Sees the World

  • Black and White only. No shades of gray.
  • Loss of detail.
  • Loss of accuracy when reading data
mark sense black and white image
Mark Sense Black and White Image

Can you tell which are the intended marks? The answers will be shown 2 slides from now.

  • Bitone. Only Black and White.
  • Cannot tell the difference between an erasure and an intended mark.
  • Mark Sense loss of detail causes multiple marks when erasures are intended.
  • Mark Sense is a poor choice for high stakes testing.
mark sense read bi tone original
Mark Sense Read Bi-Tone Original

Scanner Normal Threshold

Reads Bubble 5

Omit

mark sense read bi tone original1
Mark Sense Read Bi-Tone Original

Scanner Low Threshold

Multiple

Reads Bubble 3

slide7

How Mark Sense Sees the World

  • Black and White only. No shades of gray.
  • Loss of detail.
  • Loss of accuracy when reading data
slide8

How True OMR Sees the World

  • Grayscale. Black, White, and various shades of gray in between.
  • Increase in detail.
  • Increase in accuracy when reading data.
true omr grayscale
True OMR Grayscale

Correct Responses:

D

E

D

OMR

Mark Sense

Mark sense would have read: mult, C, mult, A, mult, for 3 wrong reads.

OMR would have read: D, C, E, A, D for 5 accurate reads.

  • true OMR has 16 level grayscale read.
  • true OMR can accurately tell the difference between an erasure and an intended mark.
  • true OMR’s increase in detail causes increase in read accuracy.
  • true OMR is ideal for high stakes testing.
what about light marks
What About Light Marks?

Original Mark as seen on sheet

Bitone Mark Sense Reads as Omit

true OMR Reads a Valid Mark

Marks that are light can be dropped out by bitone mark sense, and considered to be omits. Because the image will not show light marks, the actual student sheet must be retrieved for visual inspection and correction.

Because True OMR sees in grayscale, light marks will still be read as valid marks, with no user verification required.

slide11

True OMR 16 Level Read

Mark Threshold (user adjustable)

[N]ormal setting

[D]ark

setting

[L]ight setting

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

A B C D E F

Paper

* Every bubble on the form gets assigned a value from 0 through F (0 – 15)

slide12

True OMR 16 Level Read

Mark Discrimination Summary

  • If two or more valid marks are present:
    • They must be 3 levels apart or a multiple is recorded
    • If both marks are at or above the discrimination cutoff, then there was no attempt at an erasure, and a multiple is recorded.

Mark Threshold, Mark Discrimination, and Mark Discrimination Cutoff are all user definable.

slide13

True OMR Second Darkest Mark Read

  • Returns up to 3 fields:
  • Darkest Mark Field – D,B,C,D,E
  • Second Darkest Mark – A, -,E, - ,B
  • Optional Darkness Zone - 600E00F00000F08000C00600B

Formatted Output :

D,B,C,D,E,A,-,E,-,B,600E00F00000F08000C00600B,

Darkest Marks

Second Darkest Marks

Darkness Zone information (optional)

Dashes indicate omits

true omr verification
True OMR Verification
  • Because true OMR can distinguish between an intended mark and an erasure, and is capable of reading light marks as well, manual verification of data is not required.
    • Saves time
    • Reduces the chances of human error
  • True OMR can still be verified if desired.