Objeck Documentation

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Bundle OpenCV computer vision library. Image supports loading, saving, resizing, color conversion, blurring, edge detection, cropping, and drawing. VideoCapture reads from files or camera streams. Compile with -lib opencv.

Image

OpenCV image

Operations

AdaptiveThreshold
BilateralFilter
BoundingRect
Bytes
Canny
Clone
Columns
ContourArea
Convert
Crop
CvtColor
Dilate
DrawCircle
DrawContours
DrawRectangle
DrawText
Erode
FindContours
Flip
GaussianBlur
GetRotationMatrix2D
IsEmpty
Load
MedianBlur
MorphologyEx
Normalize
Resize
Rows
Save
Show
Size
Sobel
Threshold
Type
WarpAffine
WarpPerspective

AdaptiveThreshold #

Applies an adaptive threshold to an array

method : public : AdaptiveThreshold(maxval:Float, adaptive_method:Int, threshold_type:Int, block_size:Int, C:Float) ~ Image

Parameters

Name	Type	Description
maxval	Float	non-zero value assigned to pixels that satisfy the condition
adaptive_method	Int	adaptive thresholding algorithm (0=MEAN_C, 1=GAUSSIAN_C)
threshold_type	Int	threshold type (must be BINARY or BINARY_INV)
block_size	Int	size of the pixel neighborhood (must be odd and greater than 1)
C	Float	constant subtracted from the mean or weighted mean

Return

Type	Description
Image	thresholded image

BilateralFilter #

Applies bilateral filter to the image

method : public : BilateralFilter(d:Int, sigmaColor:Float, sigmaSpace:Float) ~ Image

Parameters

Name	Type	Description
d	Int	diameter of each pixel neighborhood
sigmaColor	Float	filter sigma in the color space
sigmaSpace	Float	filter sigma in the coordinate space

Return

Type	Description
Image	filtered image

BoundingRect # function

Computes the bounding rectangle for a single contour.

function : BoundingRect(contours:Int[], index:Int) ~ Rect

Parameters

Name	Type	Description
contours	Int	packed contour data from FindContours()
index	Int	index of the contour

Return

Type	Description
Rect	bounding rectangle

Bytes #

Gets image bytes

method : public : Bytes() ~ Byte[]

Return

Type	Description
Byte	image bytes

Canny #

Applies Canny edge detection

method : public : Canny(threshold1:Float, threshold2:Float) ~ Image

Parameters

Name	Type	Description
threshold1	Float	first threshold for hysteresis procedure
threshold2	Float	second threshold for hysteresis procedure

Return

Type	Description
Image	edge-detected image

Example

image := Image->Load("photo.jpg");
gray := image->CvtColor(6);
edges := gray->Canny(50.0, 150.0);
edges->Save("edges.png");

Clone #

Creates a deep copy of the image

method : public : Clone() ~ Image

Return

Type	Description
Image	cloned image

Columns #

Gets image columns

method : public : Columns() ~ Int

Return

Type	Description
Int	image columns

ContourArea # function

Computes the area of a single contour.

function : ContourArea(contours:Int[], index:Int) ~ Float

Parameters

Name	Type	Description
contours	Int	packed contour data from FindContours()
index	Int	index of the contour

Return

Type	Description
Float	area of the contour

Convert #

Convert an image to a given byte format

method : public : Convert(format:Image->Format) ~ Byte[]

Parameters

Name	Type	Description
format	Image->Format	output format

Return

Type	Description
Byte	converted image bytes

Example

image := Image->Load("photo.jpg");
png_bytes := image->Convert(Image->Format->PNG);
"PNG bytes: {$png_bytes->Size()}"->PrintLine();

Crop #

Crops an image using a rectangle region of interest

method : public : Crop(rect:Rect) ~ Image

Parameters

Name	Type	Description
rect	Rect	bounding rectangle for the crop region

Return

Type	Description
Image	cropped image

Example

image := Image->Load("photo.jpg");
region := Rect->New(10, 10, 200, 150);
cropped := image->Crop(region);
cropped->Save("cropped.jpg");

CvtColor #

Converts image color space

method : public : CvtColor(code:Int) ~ Image

Parameters

Name	Type	Description
code	Int	color conversion code from ColorConversionCodes

Return

Type	Description
Image	converted image

Example

image := Image->Load("photo.jpg");
gray := image->CvtColor(6);
gray->Save("gray.png");

Dilate #

Dilates an image using a structuring element

method : public : Dilate(shape:Int, ksize_w:Int, ksize_h:Int) ~ Image

Parameters

Name	Type	Description
shape	Int	structuring element shape from MorphShapes
ksize_w	Int	kernel width
ksize_h	Int	kernel height

Return

Type	Description
Image	dilated image

DrawCircle #

Draws a bounding circle

method : public : DrawCircle(pt:Point, radius:Int, color:Scalar, thickness:Int, type:LineType) ~ API.OpenCV.Image

Parameters

Name	Type	Description
pt	Point	circle center
radius	Int	circle radius
color	Scalar	bounding circle color
thickness	Int	bounding circle thickness
type	LineType	bounding circle type

Return

Type	Description
Image	updated image

DrawContours #

Draws contours on the image.

method : public : DrawContours(contours:Int[], contourIdx:Int, color:Scalar, thickness:Int) ~ Image

Parameters

Name	Type	Description
contours	Int	packed contour data from FindContours()
contourIdx	Int	index of contour to draw, or -1 to draw all contours
color	Scalar	drawing color
thickness	Int	line thickness (default 1)

Return

Type	Description
Image	image with contours drawn

DrawRectangle #

Draws a bounding rectangle

method : public : DrawRectangle(rect:Rect, color:Scalar, thickness:Int, type:LineType) ~ API.OpenCV.Image

Parameters

Name	Type	Description
rect	Rect	bounding rectangle
color	Scalar	bounding rectangle color
thickness	Int	bounding rectangle thickness
type	LineType	bounding rectangle type

Return

Type	Description
Image	updated image

Example

image := Image->Load("photo.jpg");
box := Rect->New(50, 50, 100, 80);
red := Scalar->New(0.0, 0.0, 255.0);
annotated := image->DrawRectangle(box, red, 2);
annotated->Save("annotated.jpg");

DrawText #

Draws text on an image

method : public : DrawText(text:String, font:Font, color:Scalar, thickness:Int, type:LineType) ~ API.OpenCV.Image

Parameters

Name	Type	Description
text	String	text to draw
font	Font	text font
color	Scalar	bounding circle color
thickness	Int	bounding circle thickness
type	LineType	bounding circle type

Return

Type	Description
Image	updated image

Example

image := Image->Load("photo.jpg");
white := Scalar->New(255.0, 255.0, 255.0);
labeled := image->DrawText("Hello!", Point->New(10, 30), Font->FONT_HERSHEY_SIMPLEX, 1.0, white);
labeled->Save("labeled.jpg");

Erode #

Erodes an image using a structuring element

method : public : Erode(shape:Int, ksize_w:Int, ksize_h:Int) ~ Image

Parameters

Name	Type	Description
shape	Int	structuring element shape from MorphShapes
ksize_w	Int	kernel width
ksize_h	Int	kernel height

Return

Type	Description
Image	eroded image

FindContours #

Finds contours in a binary image. The image should be single-channel (e.g., after CvtColor to grayscale and Threshold). Returns a packed Int[] with format: [count, size0..sizeN-1, x0,y0,x1,y1,...]. Use ContourArea() and BoundingRect() to analyze individual contours.

method : public : FindContours(mode:Int, approx:Int) ~ Int[]

Parameters

Name	Type	Description
mode	Int	contour retrieval mode from RetrievalModes
approx	Int	contour approximation method from ContourApproximationModes

Return

Type	Description
Int	packed Int[] representing the detected contours

Flip #

Flips an image

method : public : Flip(flipCode:Int) ~ Image

Parameters

Name	Type	Description
flipCode	Int	0 for vertical, 1 for horizontal, -1 for both

Return

Type	Description
Image	flipped image

Example

image := Image->Load("photo.jpg");
mirrored := image->Flip(1);
mirrored->Save("mirrored.jpg");

GaussianBlur #

Applies Gaussian blur to the image

method : public : GaussianBlur(ksize_w:Int, ksize_h:Int, sigmaX:Float) ~ Image

Parameters

Name	Type	Description
ksize_w	Int	kernel width (must be odd)
ksize_h	Int	kernel height (must be odd)
sigmaX	Float	Gaussian kernel standard deviation in X direction

Return

Type	Description
Image	blurred image

Example

image := Image->Load("photo.jpg");
blurred := image->GaussianBlur(5, 5, 1.5);
blurred->Save("blurred.jpg");

GetRotationMatrix2D # function

Computes a 2D rotation matrix for an affine transformation.

function : GetRotationMatrix2D(center_x:Float, center_y:Float, angle:Float, scale:Float) ~ Float[]

Parameters

Name	Type	Description
center_x	Float	x-coordinate of the rotation center
center_y	Float	y-coordinate of the rotation center
angle	Float	rotation angle in degrees (positive counter-clockwise)
scale	Float	isotropic scale factor

Return

Type	Description
Float	6-element Float[] representing the 2x3 rotation matrix

IsEmpty #

Determines if an image is empty

method : public : IsEmpty() ~ Bool

Return

Type	Description
Bool	true if empty, false otherwise

Load # function

Load image from file

function : Load(image_path:String) ~ API.OpenCV.Image

Parameters

Name	Type	Description
image_path	String	image file path

Return

Type	Description
Image	loaded image

Example

image := Image->Load("photo.jpg");
if(<>image->IsEmpty()) {
  "Loaded: {$image->Columns()}x{$image->Rows()}"->PrintLine();
};

Load # function

Load image from bytes

function : Load(image_bytes:Byte[]) ~ API.OpenCV.Image

Parameters

Name	Type	Description
image_bytes	Byte	raw image bytes

Return

Type	Description
Image	loaded image

Example

raw := System.IO.Filesystem.FileReader->ReadBinaryFile("photo.jpg");
image := Image->Load(raw);
"Rows: {$image->Rows()}, Cols: {$image->Columns()}"->PrintLine();

MedianBlur #

Applies median blur to the image

method : public : MedianBlur(ksize:Int) ~ Image

Parameters

Name	Type	Description
ksize	Int	aperture size (must be odd and greater than 1)

Return

Type	Description
Image	blurred image

Example

image := Image->Load("noisy.jpg");
denoised := image->MedianBlur(3);
denoised->Save("denoised.jpg");

MorphologyEx #

Applies a morphological operation to an image

method : public : MorphologyEx(op:Int, shape:Int, ksize_w:Int, ksize_h:Int) ~ Image

Parameters

Name	Type	Description
op	Int	morphological operation type from MorphTypes
shape	Int	structuring element shape from MorphShapes
ksize_w	Int	kernel width
ksize_h	Int	kernel height

Return

Type	Description
Image	processed image

Normalize #

Normalizes the image for neural network preprocessing. Converts the image to float, normalizes to [0,1], converts BGR to RGB, subtracts the given mean values, and divides by the given std values per channel. Returns the result as a flattened CHW tensor (Float[]).

method : public : Normalize(mean_r:Float, mean_g:Float, mean_b:Float, std_r:Float, std_g:Float, std_b:Float) ~ Float[]

Parameters

Name	Type	Description
mean_r	Float	mean value for the red channel
mean_g	Float	mean value for the green channel
mean_b	Float	mean value for the blue channel
std_r	Float	standard deviation for the red channel
std_g	Float	standard deviation for the green channel
std_b	Float	standard deviation for the blue channel

Return

Type	Description
Float	flattened CHW Float[] tensor suitable for ONNX inference

Resize #

Resizes an image

method : public : Resize(sz:Size, fx:Float, fy:Float, interpolation:InterpolationFlags) ~ API.OpenCV.Image

Parameters

Name	Type	Description
sz	Size	image size
fx	Float	x-scale factor
fy	Float	y-scale factor
interpolation	InterpolationFlags	filling missing pixels method

Return

Type	Description
Image	updated image

Example

image := Image->Load("photo.jpg");
resized := image->Resize(Size->New(320, 240));
resized->Save("thumb.jpg");

Resize #

Resizes an image

method : public : Resize(fx:Float, fy:Float, interpolation:InterpolationFlags) ~ API.OpenCV.Image

Parameters

Name	Type	Description
fx	Float	x-scale factor
fy	Float	y-scale factor
interpolation	InterpolationFlags	filling missing pixels method

Return

Type	Description
Image	updated image

Resize #

Resizes an image

method : public : Resize(f:Float, ) ~ API.OpenCV.Image

Parameters

Name	Type	Description
f	Float	scale factor

Return

Type	Description
Image	updated image

Rows #

Gets image rows

method : public : Rows() ~ Int

Return

Type	Description
Int	image rows

Save #

Saves an image to file

method : public : Save(path:String) ~ Bool

Parameters

Name	Type	Description
path	String	output file path

Return

Type	Description
Bool	true if saved successfully, false otherwise

Example

image := Image->Load("input.jpg");
blurred := image->GaussianBlur(5, 5, 1.5);
if(blurred->Save("output.jpg")) {
  "Saved."->PrintLine();
};

Show #

Shows an image

method : public : Show(title:String) ~ Nil

Parameters

Name	Type	Description
title	String	dialog title

Example

image := Image->Load("photo.jpg");
image->Show("Preview");

Show #

Shows an image

method : public : Show(title:String, scale:Float) ~ Nil

Parameters

Name	Type	Description
title	String	dialog title
scale	Float	scaling percentage

Show #

Shows an image

method : public : Show(title:String, scale:Float, ) ~ Nil

Parameters

Name	Type	Description
title	String	dialog title
scale	Float	scaling percentage

Size #

Gets image size

method : public : Size() ~ Int

Return

Type	Description
Int	image size

Sobel #

Applies Sobel edge detection

method : public : Sobel(ddepth:Int, dx:Int, dy:Int) ~ Image

Parameters

Name	Type	Description
ddepth	Int	desired depth of the destination image (use -1 for same as source)
dx	Int	order of the derivative x
dy	Int	order of the derivative y

Return

Type	Description
Image	edge-detected image

Threshold #

Applies a fixed-level threshold to each array element

method : public : Threshold(thresh:Float, maxval:Float, type:Int) ~ Image

Parameters

Name	Type	Description
thresh	Float	threshold value
maxval	Float	maximum value to use with BINARY and BINARY_INV threshold types
type	Int	threshold type from ThresholdTypes

Return

Type	Description
Image	thresholded image

Type #

Gets image type

method : public : Type() ~ Int

Return

Type	Description
Int	image type

WarpAffine #

Applies an affine transformation to the image using a 2x3 matrix.

method : public : WarpAffine(matrix:Float[], width:Int, height:Int) ~ Image

Parameters

Name	Type	Description
matrix	Float	6-element Float[] representing the 2x3 affine matrix (row-major)
width	Int	output image width
height	Int	output image height

Return

Type	Description
Image	transformed image

WarpPerspective #

Applies a perspective transformation to the image using a 3x3 matrix.

method : public : WarpPerspective(matrix:Float[], width:Int, height:Int) ~ Image

Parameters

Name	Type	Description
matrix	Float	9-element Float[] representing the 3x3 perspective matrix (row-major)
width	Int	output image width
height	Int	output image height

Return

Type	Description
Image	transformed image