Image Filtering
Comparison of ISP HW
vs
Almalence SW filters
+
Tasks sharing between ISP
And
Almalence Imaging Libraries
Features chart
ISP HW
Almalence SW
Multishot-compatible
No
Yes
Lens shading taken
into account
Rarely
Yes
Easily configurable
No
Yes
Typical ISP pipeline
RAW
Sensor
ADC
Optical
clamp
Scale
Denoise
Colorspace
convert
Gamma
correct
RGB
to
YUV
Sharpen
Chroma
subsample
Black
level
sub
Faulty
Pixel
correct
Lens
shading
correct
Debayer
Culling
&
Binning
Red-tinted blocks are filters
JPEG
enc
ISP function with Super-Resolution
-SR utilizes image data preserved due to absence of filters
-SR replaces the filters with better ones
SR processing
RAW
Sensor
ADC
Optical
clamp
ColorGamma
Scale Denoise space
correct
convert
RGB
to
YUV
Sharpen
Chroma
JPEG
subenc
sample
Black
level
sub
Faulty
Pixel
correct
Lens
shading
correct
Debayer
Align
Deghost
Denoise
Enhance
edges
Fuse
Culling
&
Binning
Standard filters should be turned
off to preserve image data
needed for SR
SR processing includes
Denoise and Sharpening.
JPEG
enc
Real life comparison
Example images below have been taken with Galaxy Nexus

Stock firmware

Jelly Bean Android
Noise filter – HW ISP
Lens shading correction not taken into account
Center
Corner: noise outbursts
Noise filter – Almalence
Lens shading taken in account
Center
Corner
Noise filter – Almalence
Easily configured (API accessible from application layer)
No filtering
Little filtering
High filtering
Noise filter – Almalence
SW flexibility allows for more complex algorithms
Filtered with HW:
Some noise remaining,
Some details lost
Filtered with Almalence NF:
Complete removal of noise
Details remain
Sharpening filter – HW ISP
Downscaled full image looks good
Close look – oversharpening evident (halos)
Sharpening filter – Almalence
Close look – edges are enhanced, no halos
Super-resolution compatibility
SR result with pre-filtered images: loss
of details, over-sharpen exaggerated
SR result with post-filtering