FamilySearch Scanning (Scanstone) An Automated Exposure Method For - PowerPoint PPT Presentation

FamilySearch Scanning (Scanstone) An Automated Exposure Method For Scanning Microfilm Heath Nielson nielsonhe@ldschurch.org

Digitizing Microfilm � Scan as efficiently as possible – At 30 minutes a roll, it would require a single scanner 142 years of constant scanning to scan 2.5 million rolls � Maintain consistent (good) quality – Adjust lamp level

Changing light level Lamp level: 160 150 190 140 130 120 110 100 170 250 240 230 220 210 200 180 80 90

Goal � To maintain efficiency and quality, we need to automatically identify the optimal lamp setting for a given film � Optimal lamp level is dependent upon: – Film density – Focal length – Light output

Film Density ( i I ) � Amount of incident light transmitted through the film ( t I ) D is measured in terms of optical density ⎛ ⎞ I ⎜ ⎟ = ≤ D ≤ ∞ i D log 0 ⎜ ⎟ ⎝ ⎠ I t ≈ − ≈ − 0 . 80 1 . 80 D D 0 . 07 0 . 28 max min (15%-1%) (85%-52%) � Film Contrast is dependent upon range between D and D min max

Density vs. Lamp Level Histogram View 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 250 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity Intensity 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp Lamp ≈ ≈ D 1 . 40 D 0 . 16 max min

Density Test � Created test film comprised of 17 sections – The density of each section was constant – The sections represented a range of densities from 0.03 to 1.50 � Film was scanned multiple times across a range of different lamp levels � The mean intensity for each density was calculated

Density Roll

Result of Test Roll 200DPI-16x 0.03 300.0 0.20 0.30 250.0 0.40 0.50 0.60 200.0 0.70 Intensity 0.80 150.0 0.90 0.95 100.0 1.00 1.05 1.10 50.0 1.15 1.20 0.0 1.30 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 1.40 Lamp 1.50

Focal length � Camera and lens move Camera – Affects the amount of light received by the camera Lens – Position is determined by the selected DPI and reduction ratio of the film prior to scanning

Focal Length vs. Lamp Level 200DPI-42x 200DPI-12x 200DPI-16x 200DPI-10x 200DPI-24x 0.03 0.03 0.03 0.03 0.03 300.0 300.0 300.0 300.0 300.0 0.20 0.20 0.20 0.20 0.20 0.30 0.30 0.30 0.30 0.30 250.0 250.0 250.0 250.0 250.0 0.40 0.40 0.40 0.40 0.40 0.50 0.50 0.50 0.50 0.50 0.60 0.60 0.60 0.60 0.60 200.0 200.0 200.0 200.0 200.0 0.70 0.70 0.70 0.70 0.70 Intensity Intensity Intensity Intensity Intensity 0.80 0.80 0.80 0.80 0.80 150.0 150.0 150.0 150.0 150.0 0.90 0.90 0.90 0.90 0.90 0.95 0.95 0.95 0.95 0.95 100.0 100.0 100.0 100.0 100.0 1.00 1.00 1.00 1.00 1.00 1.05 1.05 1.05 1.05 1.05 1.10 1.10 1.10 1.10 1.10 50.0 50.0 50.0 50.0 50.0 1.15 1.15 1.15 1.15 1.15 1.20 1.20 1.20 1.20 1.20 0.0 0.0 0.0 0.0 0.0 1.30 1.30 1.30 1.30 1.30 80 80 80 80 80 90 90 90 90 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 1.40 1.40 1.40 1.40 1.40 Lamp Lamp Lamp Lamp Lamp 1.50 1.50 1.50 1.50 1.50

Scanner Light Output � Light output is inconsistent across Scanners Compared - Lumens 1400.00 scanners 1200.00 1000.00 � Mechanical differences Lumens 800.00 – Presence of diffuser 600.00 400.00 – Out of calibration 200.00 0.00 – Age of lamp 64 128 192 255 Lamp Level S01 S02 S03 S04 S05 S06 S07 S08 S09 S10

Developing an Exposure Strategy � Input – Unknown film density – Variable focal length – Inconsistent light output across scanners � Output – Inter-frame background and handwriting with an intensity ~0 – Frame background with an intensity ~200 or greater � How should the lamp be adjusted?

Histogram Stretching � Set the lamp to an “average” value for the selected focal length � Scan the film � Find the mode of the black and white ( x b x , ) distributions w � Create a stretching function to remap the scanned pixel data 200 = = − a y a ( x x ) − b x x w b