Color Imaging - Getting the Best from Multi-Sensor Prism Cameras
Paritosh Prayagi Christian Felsheim Product Manager VP Sales EMEA
2017 – H2 Color Imaging Technologies Overview
Cameras with On-Pixel Filtering Multi-line Cameras Multi-Sensor Prism Cameras
R
Optics G Bayer-Pattern Sensor
B Imec Mosaic hyperspectral sensor On-Pixel-Filtering Cameras Bayer-Pattern
Compact on-sensor color filtering High volume -> low price Sensors with high pixel count available offering large field-of-view (FOV)
Most of the light hitting the sensor is blocked and thus lost Color information needs to be interpolated from neighbouring pixels Cross talk between neighbouring pixel resulting in color channel cross talk GbBGbB RGrRGr Inter True Inter- GbBGbB polated green polated RGrRGr 3 Multi-Line Cameras
Full color information in every pixel Compact on-sensor color filtering Flexibel: 2 – n lines possible
Line scan, only Halo artefacts when • camera is not oriented perpendicular to web • objects are moving unpredictable (e.g. free-fall objects) • 3D objects imaged HALOHALOHALOHALO
4 Multi-Sensor Prism Cameras
Full color information in every pixel ! Better color contrast and differentiation R Line and Area scan cameras available No halo effects Light is sperated not blocked off -> high sensitivity No crosstalk between color channels Optics G Full color resolution Customizable color seperation
Higher price B Optimized lens required Larger housing Limited pixel count resulting in smaller FOV 5 Getting the Best out Muli-Sensor Prism Cameras
R • Select the right lens
• Optimize S/N and color contrast
• Optimize color seperation Optics • Optimize color channel bandwidth G
• On-camera color processing functions
• Robostness of Prism Cameras B
6 Lenses Optimized for Multi-Sensor Cameras
Single-Sensor Lens Multi-Sensor Lens
Smaller angle to optical axis
Lens Lens exit pupil exit pupil
Single-sensor lenses have a smaller exit pupil, Multi-sensor lenses have a larger exit pupil, resulting into a larger angle of light rays passing resulting into a smaller angle of light rays passing through the dichroic prism through the dichroic prism 7 Chromatic Abberations Caused by Lenses NOT Optimized for Multi-Sensor Cameras
240
180
120 • Prism introduces colour 60 shading
0 (0,23) (1023,23) • Colour shading caused by
256 dichroic filters 192 • Degree of colour shading 128 depends on angle of light 64 rays passing through the 0 (0,371) (1023,371) dichroic layer
256 • Single sensor lenses have 192
128 small exit pupil, resulting
64 into larger angle of light
0 rays passing through (0,748) (1023,748) dichroic layer
240 256 240
180 192 180
120 128 120
60 64 60
0 0 0 8 (26,0) (24,767) (495,0) (495,767) (1004,0) (1004,767) Lenses Optimized for Multi-Sensor Cameras do not Drop in MTF
Single-Sensor Lens
Multi-Sensor Lens
3CCD/CMOS lens Single Single sensorlens
https://www.fujifilmusa.com/shared/bin/3CCD%20Camera%20Lens.pdf
9 Manufactureres offering Multi-Sensor optimized Lenses
10 Optimize S/N and Color Contrast Silicon Sensitivity Decays in Blue and Red
Sony Pregius IMX 249 Absolute QE Absolute
11 Otimize S/N and Color Contrast Adjust gain and exposure time seperately
CCD Output Gain Optimized Gain and Exposure Time Optimized 100 % -3dB Level -6dB
Signal Signal Signal
Noise Noise 0 % Noise B G R B G R B G R +3dB 0dB +6dB +2dB 0dB +3dB 7ms 5ms 9ms Gain and exposure time can be adjusted for every sensor / color channel seperately in ordere optimize S/N and color contrast 12 Optimized S/N and Color Contrast
Bayer Pattern Multi-Sensor Prism Camera
13 Optimize Color Separation Steepen filter bandwidth
Bayer Pattern Camera 1.0 R 0.8
0.6
0.4
Relative Response Relative 0.2
0 400 450 500 550 600 650 700 Optics G Wavelength (nm) Prism Camera 1.0
0.8
0.6
0.4 B Relative Response Relative 0.2 0 14 400 450 500 550 600 700 Wavelength (nm) Optmized Color Differentiation
Bayer Pattern Multi-Sensor Prism Camera
15 Optimize Color Channel Width Shape bandwidth by adding filters
Standard Shaped Bands
CCD 1 CCD 2 CCD 3 CCD 1 CCD 3 CCD 2
Optics
λ1 λ2 λ3 λ1 λ2 λ3
16 Optimize Color Channel Width Bandwidth shaped to fluorescence dye emission band
17 Other Color Channel Bandwidth Seperations
3 Sensor B-G,R,NIR 2 Sensor RGB + NIR 2 InGaAs Sensors SWIR
Sugar Salt Rel. Sensitivity Rel.
300 400 500 600 700 800 900 1000 Wavelength [nm]
4 Sensor B,G,R,NIR 3 Sensor RGB,NIR,NIRSimulation_20170727 100 900 nm – 1400 nm 1400 nm – 1700 90 nm 80 70 60 50 40
30
Rel. Sensitivity Rel. Transmission [%] Transmission 20 10 0 300 400 500 600 700 800 900 1000 300 400 500 600 700 800 900 1000 18 Wavelength [nm] Wavelength [nm] On-Camera Color Processing Functions
Some prism cameras offer on-head features to further improve color imaging: I
• Color Space Conversion – RGB to L*a*b – RGB to HSI – RGB to CIE-XYZ – RGB to sRGB, Adobe RGB – Hue enhancement
19 Robustness of Prism-Cameras in Industrial Applications ??
Ask for vibration and shock and temperatur stability !!
+45°C VIBRATION SHOCK
3G 50G -5°C
Highly Robust Prism Industrial Cameras are Available ! 20 JAI Color Imaging Portefolio All technologies available from one supplier
AREA SCAN CAMERAS LINE SCAN CAMERAS
APEX 3 SWEEP+ 3 & 4 R-G-B Sensor R-G-B + NIR Sensor
FUSION Dual WAVE Dual Bayer RGB/NIR SWIR (InGaAs) Monochrome Sensor SWIR
SPARK Perfor- SWEEP TriTri-- Bayer RGB mance COLOR linear Monochrome linear
GO SWEEP Mono Bayer RGB Compact MONOCHROME Monochrome chrome
21 THANK YOU for seeing the possibilities
Christian Felsheim Paritosh Prayagi
[email protected] [email protected]
www.jai.com