Update README.md

# python3-escher-pattern

Escher or checker board pattern generator

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Generates:

* Escher pattern

* Checker board pattern

Used for camera systems optical calibration.

Outputs is a PDF file. No borders. Ready for printing.

# Recommendations

* Overall pattern rotation angle 0 is bad for correct MTF computation - because sensor pixel grid

# Requirements

* matplotlib

# Usage

## Docker

```

docker build --tag ep .

docker run -d -p 3113:5000 ep

```

Then:

```

http://localhost:3113/?PAGE_WIDTH=1524&PAGE_HEIGHT=3048&LPM=2.705449885575893&ROTATE=14.036243467

```

Parameters:

* **PAGE_WIDTH**  - page width in mm

* **PAGE_HEIGHT** - page width in mm

* **LPM**         - cell pairs per meter

* **ROTATE**      - pattern rotation angle

* **ESCHER**      - cell border curvature - at 0 or inf becomes a normal checker board. Max curvature is at ~2.4. Optimal - 2.0

## Command line

escher.py:

```

from escher_pattern import Escher_Pattern

ep = Escher_Pattern(width= 1524, height= 3048, escher=2, lpm=2.705449885575893, rotate=14.036243467)

ep.generate()

ep.save()

```

checkerboard.py:

```

from escher_pattern import Escher_Pattern

ep = Escher_Pattern(width= 1524, height= 3048, escher=0, lpm=2.705449885575893, rotate=14.036243467)

ep.generate()

ep.save()

```

Parameters:

* **width**  - page width in mm

* **height** - page width in mm

* **lpm**    - cell pairs per meter

* **rotate** - pattern rotation angle

* **escher** - cell border curvature - at 0 or inf becomes a normal checker board. Max curvature is at ~2.4. Optimal - 2.0