Dark Subtraction

Detailed documentation ALS DarkRemove process

Overview

The DarkRemove process subtracts the thermal noise from the image using a user-provided master dark.

Its configuration is managed via ALS preferences page.

Configuration

	Source	Data type	Required	Default value
ON/OFF	Preferences: Processing Tab	ON/OFF	∅	OFF
Master dark path	Preferences: Processing Tab	File path	Yes	∅

Control

This process is triggered by the Preprocess pipeline.

Input

Data	Type
image received from the Preprocess pipeline	Image
master dark read from configured path	Image

Behavior

graph LR

START([START])

TEST_ENABLED{{Processing enabled?}}
TEST_SIZE{{Identical dimensions?}}
TEST_TYPE{{Identical data types?}}

CONVERT[Convert master dark]
SUBTRACT[Subtract master dark from image]

RETURN[Return modified image]
UNCHANGED[Return unchanged image]

END([END])

START --> TEST_ENABLED

TEST_ENABLED ----->|No| UNCHANGED
TEST_ENABLED -->|Yes| TEST_SIZE

TEST_SIZE ----->|No| UNCHANGED
TEST_SIZE -->|Yes| TEST_TYPE

TEST_TYPE -->|No| CONVERT
TEST_TYPE -->|Yes| SUBTRACT

CONVERT --> SUBTRACT
SUBTRACT --> RETURN

RETURN --> END
UNCHANGED --> END

classDef bounds fill: #333, stroke: #666, stroke-width: 2px, color: #BBB, font-family: 'Poppins', sans-serif
classDef step fill: #444, stroke: #622, stroke-width:2px, color: #c6c6c6, font-family: 'Poppins',sans-serif
classDef wait  fill: #444, stroke: #262,stroke-width: 2px, color: #c6c6c6, font-family:'Poppins', sans-serif
classDef test fill: #444, stroke: #226, stroke-width: 2px, color: #c6c6c6, font-family: 'Poppins', sans-serif

class TEST_ENABLED,TEST_SIZE,TEST_TYPE test
class START,END bounds
class RETURN,UNCHANGED,CONVERT,SUBTRACT step

The master dark is subtracted from the image.

If data types are different, the master dark is converted to the same data type as the image before subtraction.
If dimensions are different, the process is aborted and the unmodified image is sent back to the Preprocess module.

Output

The modified image is sent back to the Preprocess pipeline.