ImageMath Functions

This page describes the built-in functions available in ImageMath scripts.

Solar Image Reconstruction

IMG

Returns the reconstructed image at the specified pixel offset.

Argument

Required?

Description

Default value

ps

Pixel shift

Examples

img(0)

img(ps: 1)

img(ps: a2px(1)) // 1 Å pixel shift

RANGE

Returns the reconstructed image at the pixel offsets represented by the interval.

Argument

Required?

Description

Default value

from

to

End of the interval (inclusive)

step

Step of the interval

Examples

range(-1;1)

range(-1;1;0.5))

range(from: -10; to: 10; step: 2)

Math functions

AVG

Computes the average of its arguments. If the arguments are images, the average is computed pixel-wise.

Argument

Required?

Description

Default value

list

Arguments

Examples

avg(range(-1;1))

avg(img(0); img(1))

CONCAT

Concatenates argument lists.

Argument

Required?

Description

Default value

list

Arguments

Examples

concat(list(img(0));range(-1;1))

EXP

Computes an exponential

Argument

Required?

Description

Default value

v

Value

exp

Exponent

Examples

exp(img(0); 1.5)

exp(v:img(0), exp: 2)

exp(2, 3)

exp(v:2, exp: 3)

LOG

Computes a logarithm

Argument

Required?

Description

Default value

v

Value

exp

Exponent

Examples

log(img(0); 1.5)

log(v:img(0), exp: 2)

log(2, 3)

log(v:2, exp: 3)

MAX

Computes the maximum of its arguments. If the arguments are images, the maximum is computed pixel-wise.

Argument

Required?

Description

Default value

list

Arguments

Examples

max(range(-1;1))

max(img(0); img(1))

MEDIAN

Computes the median of its arguments. If the arguments are images, the median is computed pixel-wise.

Argument

Required?

Description

Default value

list

Arguments

Examples

median(range(-1;1))

median(img(0); img(1))

MIN

Computes the minimum of its arguments. If the arguments are images, the minimum is computed pixel-wise.

Argument

Required?

Description

Default value

list

Arguments

Examples

min(range(-1;1))

min(img(0); img(1))

POW

Computes a power

Argument

Required?

Description

Default value

v

Value

exp

Exponent

Examples

pow(img(0); 1.5)

pow(v:img(0), exp: 2)

pow(2, 3)

pow(v:2, exp: 3)

WEIGHTED_AVG

Computes a weighted average of images

Argument

Required?

Description

Default value

images

Images

weights

Weights

Examples

weighted_avg(range(-1;1);list(.5;1;.5))

weighted_avg(images: range(-1;1); weights: list(.5;1;.5)))

Utilities

AR_OVERLAY

Generates an overlay of the detected active regions. This feature will only work if active region image generation has been selected.

Argument

Required?

Description

Default value

img

Image(s)

labels

0 : do not display 1 : display the regions and the labels 2 : display only the labels

Examples

ar_overlay(continuum())

ar_overlay(img: img(0); labels: 2)

CHOOSE_FILE

Opens a dialog box to choose an image file.

Argument

Required?

Description

Default value

id

An ID for the file chooser. The next time the function is called with the same ID, the directory where the file chooser was opened will be used as the starting point.

message

Title of the dialog box

Examples

choose_file("my_id", "Choose a file")

choose_file(id: "my_id", title: "Choose a file")

CHOOSE_FILES

Opens a dialog box to choose multiple image files.

Argument

Required?

Description

Default value

id

An ID for the file chooser. The next time the function is called with the same ID, the directory where the file chooser was opened will be used as the starting point.

message

Title of the dialog box

Examples

choose_files("my_id", "Choose a file")

choose_files(id: "my_id", title: "Choose a file")

ELLIPSE_FIT

Triggers a new detection of the shape of the solar disk.

Argument

Required?

Description

Default value

img

Image(s)

Examples

ellipse_fit(img(0))

ellipse_fit(img:range(0;1))

FILTER

The filter function can be used on a list of images to keep these which match a particular criteria. This can be particularly useful in batch mode. For example, you may want to perform a vertical and horizontal flip to images after a certain time, because of meridian flip.

Argument

Required?

Description

Default value

img

List of images to filter.

subject

Sbject of the filter (file-name, dir-name, pixel-shift, time or datetime).

function

Operator to apply to filter the images.

value

Value for comparison

Subject Description Available operators Example

file-name

The name of the SER file

=, `

=, `contains, starts_with, ends_with

filter(images, "file-name", "contains", "2021-06-01")

dir-name

The name of the directory which contains the SER file

=, `

=, `contains, starts_with, ends_with

filter(images, "dir-name", "contains", "2021-06-01")

pixel-shift

The pixel shift of the image

=, `

=, `>, <, >=, ⇐

filter(images, "pixel-shift", ">", 0)

time

The time of the acquisition (compared in UTC)

=, `

=, `>, <, >=, ⇐

filter(images, "time", ">", "12:00:00")

datetime

The date and time of the acquisition (compared in UTC)

=, `

=, `>, <, >=, ⇐

Examples

filter(images, "file-name", "contains", "2021-06-01")

filter(img: images, subject:"file-name", function:"contains", value:"2021-06-01")

filter(images, "dir-name", "contains", "2021-06-01")

filter(imgimages, subject:"dir-name", function:"contains", value:"2021-06-01")

filter(images, "pixel-shift", ">", 0)

filter(images, "time", ">", "12:00:00")

filter(images, "datetime", ">", "2021-06-01 12:00:00")

GET_AT

Returns the value of an element in a list at the specified position.

Argument

Required?

Description

Default value

list

List

index

Index

Examples

get_at(list; 0)

get_at(list: some_list; index: 1)

GET_B

Extracts the blue channel from an image.

Argument

Required?

Description

Default value

img

Image(s)

Examples

get_b(some_image)

get_b(img: some_image)

GET_G

Extracts the green channel from an image.

Argument

Required?

Description

Default value

img

Image(s)

Examples

get_g(some_image)

get_g(img: some_image)

GET_R

Extracts the red channel from an image.

Argument

Required?

Description

Default value

img

Image(s)

Examples

get_r(some_image)

get_r(img: some_image)

LIST

Creates a list from the parameters.

Argument

Required?

Description

Default value

list

List

Examples

list(img(-3), img(3))

list(list: img(-3), img(3))

LOAD

Loads an image from a file.

Argument

Required?

Description

Default value

file

File path

Examples

load('image.fits')

load(file: '/path/to/image.fits')

LOAD_MANY

Loads many images from a directory.

Argument

Required?

Description

Default value

dir

Directory path

pattern

Regular expression to filter files

Examples

load_many("/chemin/vers/dossier")

load_many(dir: "/chemin/vers/dossier", pattern:".*cropped.*")

MONO

Converts a color image to grayscale.

Argument

Required?

Description

Default value

img

Image(s)

Examples

mono(some_image)

mono(img: some_image)

REMOTE_SCRIPTGEN

Experimental, advanced function which is described specifically in this section.

Argument

Required?

Description

Default value

url

URL of the service to invoke

Examples

remote_scriptgen("http://localhost:8080/jsolex/remote")

remote_scriptgen(url: "http://localhost:8080/jsolex/remote")

RGB

Creates an RGB image from three mono images.

Argument

Required?

Description

Default value

r

Red image

g

Green image

b

Blue image

Examples

rgb(img(-1);img(0);img(1))

rgb(r: redWing; g: avg(redWing;blueWing); b: blueWing)

SORT

Sorts a list of images

Argument

Required?

Description

Default value

images

Images

order

Sort order. One of date, shift or file_name, modulated by asc or desc.

shift

Examples

sort(images, 'date')

sort(images, 'date asc')

sort(images: images, order: 'date desc')

VIDEO_DATETIME

Returns the datetime when a video was recorded.

Argument

Required?

Description

Default value

img

Image(s)

format

Date format.

Examples

video_datetime(img(0))

video_datetime(img: img(0), format:"yyyy-MM-dd HH:mm:ss")

WAVELEN

Returns the wavelength of an image.

Argument

Required?

Description

Default value

img

Image(s)

Examples

wavelen(img(0))

wavelen(img: img(0))

WORKDIR

Changes the working directory in which images are loaded by the LOAD and LOAD_MANY functions.

Argument

Required?

Description

Default value

dir

Working directory

Examples

workdir('/path/to/dir')

workdir(dir: '/path/to/dir')

Image Enhancement

ADJUST_CONTRAST

Applies simple contrast adjustment by clipping values under the minimal value or above the maximal value.

Argument

Required?

Description

Default value

img

Image(s)

min

Minimum value

max

Maximum value

Examples

adjust_contrast(img: img(0), min: 10, max: 200)

adjust_contrast(img(0), 10, 200)

ADJUST_GAMMA

Applies a gamma correction to an image.

Argument

Required?

Description

Default value

img

Image(s)

gamma

Gamma

Examples

adjust_gamma(img: img(0), gamma: 2.2)

adjust_gamma(img(0), 1.5)

ASINH_STRETCH

Applies the inverse arcsin hyperbolic transformation to increase contrast.

Argument

Required?

Description

Default value

img

Image(s)

bp

Black point

stretch

Stretch factor

Examples

asinh_stretch(img: img(0), bp: 500, stretch: 2.5)

asinh_stretch(img(0), 0, 10)

AUTO_CONTRAST

This function is a contrast enhancement function specifically designed for spectroheliograph images.

Argument

Required?

Description

Default value

img

Image(s)

gamma

Gamma

bg

Background correction aggressiveness between 0 and 1. 1 = no correction, 0 = maximum correction.

0.25

protusStretch

Prominences enhancement. 0 means no enhancement.

Examples

auto_contrast(img: img(0), gamma: 1.5)

auto_contrast(img(0), 1.5)

BLUR

Applies a Gaussian blur to an image.

Argument

Required?

Description

Default value

img

Image(s)

kernel

Kernel size

Examples

blur(img(0))

blur(img(0), 7)

blur(img: img(0), kernel:7)

CLAHE

Applies CLAHE (Contrast Limited Adaptive Histogram Equalization) transformation to an image.

Argument

Required?

Description

Default value

img

Image(s)

ts

Tile size

bins

Bin count

clip

Clip limit

Examples

clahe(img: img(0), ts: 16, bins: 128, clip: 1.1)

clahe(img(0), 16, 128, 1.1)

COLORIZE

Applies a colorization to an image using a color profile related to the wavelength.

Argument

Required?

Description

Default value

img

Image(s)

profile

Color profile (see spectral lines editor)

Examples

colorize(img: img(0), profile: "H-alpha")

colorize(range(-1, 1), "Calcium (K)")

COLORIZE2

Applies a colorization to an image using curve modeling. The curves are defined by 2 control points: the input value and the output value.

Argument

Required?

Description

Default value

img

Image(s)

rIn

Input value for red (0-255)

rOut

Output value for red (0-255)

gIn

Input value for green (0-255)

gOut

Output value for green (0-255)

bIn

Input value for blue (0-255)

bOut

Output value for blue (0-255)

Examples

colorize2(img: img(0), rIn: 50, rOut: 200, gIn: 50, gOut: 200, bIn: 50, bOut: 200)

colorize2(img(0), 50, 200, 50, 200, 50, 200)

CURVE_TRANSFORM

Applies a curve transformation to an image. The transformation interpolates a polynomial of degree 2 passing through three points: the origin point (0,0), the curve point (in, out), and the extreme point (255,255).

Argument

Required?

Description

Default value

img

Image(s)

in

Input value of the curve (0-255)

out

Output value of the curve (0-255)

protectLo

Low protection value (0-255)

protectHi

High protection value (0-255)

Examples

curve_transform(img(0), 100, 120)

curve_transform(img: img(0), in:50, out: 200)

DISK_FILL

Fills the detected solar disk with a given value (default is the value of the detected black point).

Argument

Required?

Description

Default value

img

Image(s)

fill

Fill value

detected black point value

Examples

disk_fill(img(0))

disk_fill(img: img(0), fill: 200)

DISK_MASK

Creates a mask of the solar disk, where pixels inside the disk will have the value 1, against 0 for those outside the disk. It is possible to invert (0 inside, 1 outside) by passing 1 as the 2nd parameter of the function.

Argument

Required?

Description

Default value

img

Image(s)

invert

Inversion of the mask (1 means value 0 inside, 1 outside)

Examples

disk_mask(img(0))

disk_mask(img: img(0), invert: 1)

EQUALIZE

Equalizes the histogram of the images in parameter so that they all have about the same brightness.

Argument

Required?

Description

Default value

list

List of images to equalize.

Examples

equalize(range(-1;1))

equalize(list: some_images)

FIX_BANDING

Applies a banding correction to the image

Argument

Required?

Description

Default value

img

Image(s)

bs

Band size

passes

Number of passes

Examples

fix_banding(img(0), 64, 3)

fix_banding(img: img(0), bs: 48, passes: 10)

FIX_GEOMETRY

Applies geometric correction to the image based on the calculated ellipse

Argument

Required?

Description

Default value

img

Image(s)

Examples

fix_geometry(img(0))

fix_geometry(img: img(0))

FLAT_CORRECTION

Computes an artificial flat field image to correct the image then applies the correction.

Argument

Required?

Description

Default value

img

Image(s)

lo

Low percentile value

0.1

hi

High percentile value

0.95

order

Polynomial order

[NOTE] .Experimental ==== The artificial flat correction allows to correct a possible vignetting. It computes a model from the disk pixels. The pixels considered are those whose value is between a low and a high percentile. For example, if you enter 0.1 and 0.9, the pixels whose value is between the 10th and 90th percentile will be used to compute the model. Finally, a polynomial of the specified order is adjusted on the model values to correct the image. ====

Examples

flat_correction(img(0))

flat_correction(img: img(0), order: 3)

INVERT

Inverts the colors of an image.

Argument

Required?

Description

Default value

img

Image(s)

Examples

invert(img(0))

invert(img: img(0))

LINEAR_STRETCH

Stretches the histogram of an image to occupy the entire range of possible values. This function can also be used to compress the values of an image into the range of possible values (for example after an exponential calculation).

Argument

Required?

Description

Default value

img

Image(s)

lo

Minimum value of the histogram to stretch.

hi

Maximum value of the histogram to stretch.

65535

Examples

linear_stretch(img(0))

linear_stretch(img(0), 10000, 48000)

linear_stretch(img: img(0), hi: 48000)

RL_DECON

Applies the Richardson-Lucy deconvolution algorithm to the image.

Argument

Required?

Description

Default value

img

Image(s)

radius

Gaussian radius

2.5

sigma

Sigma

2.5

iterations

Number of iterations

Examples

rl_decon(img(0))

SATURATE

Saturates the colors of an image.

Argument

Required?

Description

Default value

img

Image(s)

factor

Saturation

Examples

saturate(img(0);1.5)

saturate(img: img(0); factor: 1.5)

SHARPEN

Applies a sharpening filter to an image.

Argument

Required?

Description

Default value

img

Image(s)

kernel

Kernel size

Examples

sharpen(img(0))

sharpen(img(0), 7)

sharpen(img: img(0), kernel:7)

Cropping

AUTOCROP

Automatically crops an image around the solar disk. The dimensions of the cropping area are determined by the ellipse but also by the dimensions of the image. It is better to use the autocrop2 function which guarantees a centered and square crop.

Argument

Required?

Description

Default value

img

Image(s)

Examples

autocrop(img: img(0))

autocrop(img(0))

AUTOCROP2

Crops an image to a centered and square area around the solar disk.

Argument

Required?

Description

Default value

img

Image(s)

factor

The width of the image will be the diameter of the solar disk multiplied by this factor.

1.1

rounding

The width of the image will be rounded to this multiple. Must be a multiple of 2.

Examples

autocrop2(img: img(0))

autocrop2(img(0))

CROP

Crops an image to the specified coordinates and dimensions.

Argument

Required?

Description

Default value

img

Image(s)

left

X coordinate of the top left corner of the cropping area.

top

Y coordinate of the top left corner of the cropping area.

width

Width of the cropping area.

height

Height of the cropping area.

Examples

crop(img(0), 10, 20, 100, 200)

crop(img: img(0), left: 10, top: 20, width: 100, height: 200)

CROP_AR

Generates a list of images corresponding to the detected sunspots.

Argument

Required?

Description

Default value

img

Image(s)

ms

Minimum size of the spot.

margin

Margin around the spot (in %).

Examples

crop_ar(continuum))

crop_ar(img:img(0), margin: 15)

CROP_RECT

Reduces the image to the specified dimensions, ensuring that the center of the solar disk will be at the center of the image. There is no scaling: if the solar disk does not fit within the target dimensions, it will be cropped.

Argument

Required?

Description

Default value

img

Image(s)

width

Width of the cropping area.

height

Height of the cropping area.

Examples

crop_rect(img(0), 1024, 1024)

crop_rect(img: img(0), width: 200, height: 200)

Background Extraction

BG_MODEL

Creates a BACKGROUND model from an image, which can be used to subtract the BACKGROUND from the original image.

Argument

Required?

Description

Default value

img

Image(s)

order

Polynomial order. A value higher than 3 is not recommended.

sigma

Number of sigmas for sample selection.

2.5

Examples

bg_model(img(0); 2.5; 3)

bg_model(img: img(0); sigma: 3)

NEUTRALIZE_BG

This is a function similar to remove_bg that uses a polynomial modeling of the background to remove gradients. This function can be used on images without ellipse information (solar disk).

Argument

Required?

Description

Default value

img

Image(s)

iterations

Number of iterations of the algorithm.

Examples

neutralize_bg(some_image)

neutralize_bg(img: img(0), iterations: 5)

REMOVE_BG

Performs background removal on an image. This can be used when the contrast is very low (e.g in helium processing) and that stretching the image also stretches the background. This process computes the average value of pixels outside the disk, then uses that to perform an adaptative suppression depending on the distance from the limb, in order to preserve light structures around the limb.

Argument

Required?

Description

Default value

img

Image(s)

tolerance

Tolerance

0.9

Examples

remove_bg(some_image)

remove_bg(img: img(0), tolerance: .5)

Rotation and Rescaling

HFLIP

Flips an image horizontally.

Argument

Required?

Description

Default value

img

Image(s)

Examples

hflip(some_image)

hflip(img: img(0))

RADIUS_RESCALE

Relative scaling method which can facilitate mosaic composition. It will therefore most likely be used in batch mode. It allows rescaling a set of images so that they all have the same solar disk radius (in pixels). In order to do so, it will perform an ellipse regression against each image to compute their solar disk, then will rescale all images to match the radius of the largest one.

Argument

Required?

Description

Default value

images

Image(s)

Examples

radius_rescale(some_image)

radius_rescale(images: my_list)

RESCALE_ABS

Rescales an image to the specified absolute dimensions.

Argument

Required?

Description

Default value

img

Image(s)

width

Width of the image

height

Height of the image

Examples

rescale_abs(img(0), 100, 100)

rescale_abs(img: img(0), width: 100, height: 100)

RESCALE_REL

Rescales an image by applying a rescaling factor.

Argument

Required?

Description

Default value

img

Image(s)

sx

Horizontal rescaling factor

sy

Vertical rescaling factor

Examples

rescale_rel(img(0), .5, .5)

rescale_rel(img: img(0), sx: 0.5, sy: 0.5)

ROTATE_DEG

Applies a rotation to an image, in degrees.

Argument

Required?

Description

Default value

img

Image(s)

angle

Angle

bp

Fill value for pixels outside of the image.

resize

Resize the image to fit the rotation.

Examples

rotate_deg(img(0); 30)

rotate_deg(img: img(0); angle: 30)

ROTATE_LEFT

Applies a left rotation to an image

Argument

Required?

Description

Default value

img

Image(s)

Examples

rotate_left(img(0))

rotate_left(img: img(0))

ROTATE_RAD

Applies a rotation to an image, in radians.

Argument

Required?

Description

Default value

img

Image(s)

angle

Angle

bp

Fill value for pixels outside of the image.

resize

Resize the image to fit the rotation.

Examples

rotate_rad(img(0); 2.1)

rotate_rad(img: img(0); angle: 2.1)

ROTATE_RIGHT

Applies a right rotation to an image

Argument

Required?

Description

Default value

img

Image(s)

Examples

rotate_right(img(0))

rotate_right(img: img(0))

VFLIP

Flips an image vertically.

Argument

Required?

Description

Default value

img

Image(s)

Examples

vflip(some_image)

vflip(img: img(0))

Analysis

A2PX

Computes the number of pixels corresponding to a distance in Angstroms. The distance is determined by calculating the dispersion, which will only be correct if you have correctly specified the pixel size of the camera, as well as your spectroheliograph.

Argument

Required?

Description

Default value

a

Angstroms

ref

Reference wavelength in Angstroms

Examples

a2px(1.2)

a2px(a: 1.2, ref: 6328)

CONTINUUM

Generates a continuum image around the studied line. This function differs from the classic continuum image in that it is not a single image calculated by the difference of fixed pixels of 15 pixels, but an image calculated from the median of a set of images.

Argument

Required?

Description

Default value

Examples

continuum()

FIND_SHIFT

Computes a pixel offset relative to the detected line. The distance is determined by calculating the dispersion, which will only be correct if you have correctly specified the pixel size of the camera, as well as your spectroheliograph.

Argument

Required?

Description

Default value

wl

Wavelength to search for in Angstroms or line name

ref

Reference wavelength in Angstroms

Examples

find_shift(5875.62)

find_shift(wl: 5875.62, ref: 5895.92)

PX2A

Computes the number of angstroms corresponding to a distance in pixels. The distance is determined by calculating the dispersion, which will only be correct if you have correctly specified the pixel size of the camera, as well as your spectroheliograph.

Argument

Required?

Description

Default value

px

pixels

ref

Reference wavelength in Angstroms

Examples

px2a(24)

px2a(px: 24, ref: 6328)

Drawing

DRAW_ARROW

Draws an arrow on the image.

Argument

Required?

Description

Default value

img

Image(s)

x1

Start of the arrow (X coordinate)

y1

Start of the arrow (Y coordinate)

x2

End of the arrow (X coordinate)

y2

End of the arrow (Y coordinate)

thickness

Thickness of the arrow

color

Color of the arrow

Examples

draw_arrow(img(0), 100, 100, 200, 200, 2, "ff0000")

draw_arrow(img:img(0), x1:100, y1:100, x2:200, y2:200, color: "ff0000")

DRAW_CIRCLE

Draws a circle on the image.

Argument

Required?

Description

Default value

img

Image(s)

cx

X coordinate of the center of the circle

cy

Y coordinate of the center of the circle

thickness

Thickness of the arrow

color

Color of the arrow

Examples

draw_circle(img(0), 100, 100, 2)

draw_circle(img:img(0), cx:100, cy:100, color: "ff0000")

DRAW_EARTH

Draws the Earth on the image, to the scale of the solar disk

Argument

Required?

Description

Default value

img

Image(s)

x

X coordinate of the center of the Earth

y

Y coordinate of the center of the Earth

Examples

draw_earth(img(0), 100, 100)

draw_earth(img:img(0), x:100, y:100)

DRAW_GLOBE

Draws a globe whose orientation and diameter correspond to the detected solar parameters.

Argument

Required?

Description

Default value

img

Image(s)

angleP

P angle

angle P

b0

b0 angle

style

Globe style. Possible values: equatorial_coords (N/S E/W corresponding to celestial N/S), solar_coords (N/S E/W corresponding to solar axes)

equatorial_coords

correctAngleP

1 to correct the P angle (the axis passing through point P is vertical), 0 otherwise

Examples

draw_globe(img(0))

draw_globe(img:img(0), angleP: 0)

DRAW_OBS_DETAILS

Displays observation details on the image

Argument

Required?

Description

Default value

img

Image(s)

x

X coordinate

y

Y coordinate

Examples

draw_obs_details(img(0), 100, 100)

draw_obs_details(img:img(0), x:100, y:100)

DRAW_RECT

Draws a rectangle on the image.

Argument

Required?

Description

Default value

img

Image(s)

left

X coordinate of the top left corner of the rectangle

top

Y coordinate of the top left corner of the rectangle

width

Width of the rectangle

height

Height of the rectangle

thickness

Thickness of the line

color

Color of the line

Examples

draw_rect(img(0), 100, 100, 300, 200)

draw_rect(img:img(0), left:100, top:100, color: "ff0000")

DRAW_SOLAR_PARAMS

Displays solar parameters on the image

Argument

Required?

Description

Default value

img

Image(s)

x

X coordinate

top right

y

Y coordinate

top right

Examples

draw_solar_params(img(0), 100, 100)

draw_solar_params(img:img(0), x:100, y:100)

DRAW_TEXT

Draws text on the image. The text can include the following variables:

%WAVELEN% : wavelength of the image in Angström (includes the shift from the reference wavelength)
%PIXELSHIFT% : pixel shift applied
%SHIFT% : shift applied (in Angström)
%RAY% : name of the observed reference line
%OBSERVER% : name of the observer
%INSTRUMENT% : name of the instrument
%TELESCOPE% : name of the telescope

Argument

Required?

Description

Default value

img

Image(s)

x

X coordinate

y

Y coordinate

text

Text to write

fs

Font size

auto

color

Color of the text

Examples

draw_text(img(0), 100, 100, "Hello %OBSERVER%!")

draw_text(img:img(0), x:100, y:100, text:"Hello %OBSERVER%!", fs: 20)

Animations

ANIM

Creates an animation from a series of images.

Argument

Required?

Description

Default value

images

The list of images

delay

Delay between each frame (in ms)

250

Examples

anim(range(0,10))

anim(images: range(0,10), delay: 100)

TRANSITION

Interpolates images between them. By default, the interpolation is linear and it will create exactly the specified number of images. However, if a unit is specified, then the behavior will be different: the number of steps corresponds to the number of images to create, for a given time unit, for the time elapsed between the two images. For example, if one image was taken at 10:00 and the other at 10:02, and the unit is ipm, that the number of steps is 10, then 20 images will be created. This allows creating smoother transitions when SER files were not recorded at regular intervals.

Argument

Required?

Description

Default value

images

Image(s)

steps

Number of intermediate images to generate.

type

Interpolation type: linear, ease_in, ease_out or ease_in_out.

linear

unit

Interpolation unit: ips (images per second), ipm (images per minute) or iph (images per hour).

Examples

transition(list(img(0), img(1)), 10)

transition(images: my_imges, steps: 10, type: ease_in, unit: 'ipm')

Stacking and mosaic composition

DEDISTORT

Allows to correct the distortion of an image. It has 2 distinct modes of use. In the first mode, it takes a reference image and an image to correct, as well as 3 optional parameters: the tile size, the sampling, and the sky background value. The returned image will be corrected as closely as possible to the reference image, making it usable for stacking, for example. In the second mode, it takes a list of images to correct and a list of already corrected images, in which case the correction parameters for each image are taken using the same index image in the list of already corrected images. This can be useful, for example, when calculating the distortion at the center of the line (shift 0) and wanting to apply the same corrections to images with different shifts.

Argument

Required?

Description

Default value

ref

Reference image(s)

img

Images to correct.

ts

Tile size

sampling

Sampling. A value of 0.5 for a tile size of 32 pixels means that there will be a sample every 16 pixels.

0.5

threshold

Sky background value.

Examples

crop_rect(img(0), 1024, 1024)

crop_rect(img: img(0), width: 200, height: 200)

MOSAIC

Creates a mosaic of images.

Argument

Required?

Description

Default value

images

Images to be assembled.

ts

Tile size

sampling

Sampling factor

0.25

Examples

mosaic(some_images)

mosaic(images: some_images, ts: 128)

STACK

Stacks multiple images.

Argument

Required?

Description

Default value

images

Images to be stacked.

ts

Tile size

sampling

Sampling factor

0.5

select

Method for selecting the best image. Can be sharpness (sharpest image), average (average of all images), median (median of all images) or eccentricity (roundest sun image). In batch mode, a manual mode is also available.

sharpness

Examples

stack(some_images)

stack(some_images, 64; .5; "eccentricity")

stack(images: some_images, ts: 128, sampling: 0.5, select: "sharpness")

STACK_REF

Selects a reference image for stacking.

Argument

Required?

Description

Default value

images

Images to be stacked.

select

sharpness

Examples

stack_ref(some_images)

stack_ref(some_images, "eccentricity")

stack_Ref(images: some_images, select: "sharpness")