Warp

Warp node is used for image warping and dewarping, which can be used to undistort images from wide FOV cameras. The node can also be used to apply a perspective transform to the image.

Compared to ImageManip node (the setWarpMesh() function):

Warp node uses underlyting warp HW block (additional docs here), with no extra resources (SHAVE/cmx cores). HW limitation: width must be divisible by 16.

ImageManip node combines the power of warp HW block together the efficiency of CMX memory to achieve higher throughput (e.g. 4k@30 fps). Scheduling of the HW block is done by SHAVE cores which also do color space conversion, type conversion (YUV420 to NV12), etc. The downside of using ImageManip node is extra RAM and SHAVE usage.

How to place it

Python

C++

pipeline = dai.Pipeline()
warp = pipeline.create(dai.node.Warp)

dai::Pipeline pipeline;
auto warp = pipeline.create<dai::node::Warp>();

Inputs and Outputs

           ┌────────────┐
inputImage │            │    out
──────────►│    Warp    ├──────►
           │            │
           └────────────┘

Message types

• inputImage - ImgFrame

• out - ImgFrame

Usage

Python

C++

pipeline = dai.Pipeline()

warp = pipeline.create(dai.node.Warp)
# Create a custom warp mesh
p1 = dai.Point2f(20, 20)
p2 = dai.Point2f(460, 20)
p3 = dai.Point2f(20, 460)
p4 = dai.Point2f(460, 460)
warp.setWarpMesh([p1,p2,p3,p4], 2, 2)
warp.setOutputSize((512,512))
warp.setMaxOutputFrameSize(512 * 512 * 3)
# Warp engines to be used (0,1,2)
warp.setHwIds([1])
# Warp interpolation mode, choose between BILINEAR, BICUBIC, BYPASS
warp.setInterpolation(dai.node.Warp.Properties.Interpolation.BYPASS)

dai::Pipeline pipeline;

auto warp = pipeline.create<dai::node::Warp>();
// Create a custom warp mesh
dai::Point2f p1(20, 20);
dai::Point2f p2(460, 20);
dai::Point2f p3(20, 460);
dai::Point2f p4(460, 460);
warp->setWarpMesh({p1,p2,p3,p4}, 2, 2);
warp->setOutputSize({512, 512});
warp->setMaxOutputFrameSize(512 * 512 * 3);
// Warp engines to be used (0,1,2)
warp->setHwIds({1});
// Warp interpolation mode, choose between BILINEAR, BICUBIC, BYPASS
warp->setInterpolation(dai::node::Warp::Properties::Interpolation::BYPASS);

Examples of functionality

• Warp Mesh

• Interactive Warp Mesh

Reference

Python

C++

class depthai.node.Warp

Warp node. Capability to crop, resize, warp, … incoming image frames

class Connection

Connection between an Input and Output

class Id

Node identificator. Unique for every node on a single Pipeline

Properties

alias of depthai.WarpProperties

getAssetManager(*args, **kwargs)

Overloaded function.

1. getAssetManager(self: depthai.Node) -> depthai.AssetManager

Get node AssetManager as a const reference

2. getAssetManager(self: depthai.Node) -> depthai.AssetManager

Get node AssetManager as a const reference

getHwIds(self: depthai.node.Warp) → List[int]

Retrieve which hardware warp engines to use

getInputRefs(*args, **kwargs)

Overloaded function.

1. getInputRefs(self: depthai.Node) -> List[depthai.Node.Input]

Retrieves reference to node inputs

2. getInputRefs(self: depthai.Node) -> List[depthai.Node.Input]

Retrieves reference to node inputs

getInputs(self: depthai.Node) → List[depthai.Node.Input]

Retrieves all nodes inputs

getInterpolation(self: depthai.node.Warp) → depthai.WarpProperties.Interpolation

Retrieve which interpolation method to use

getName(self: depthai.Node) → str

Retrieves nodes name

getOutputRefs(*args, **kwargs)

Overloaded function.

1. getOutputRefs(self: depthai.Node) -> List[depthai.Node.Output]

Retrieves reference to node outputs

2. getOutputRefs(self: depthai.Node) -> List[depthai.Node.Output]

Retrieves reference to node outputs

getOutputs(self: depthai.Node) → List[depthai.Node.Output]

Retrieves all nodes outputs

getParentPipeline(*args, **kwargs)

Overloaded function.

1. getParentPipeline(self: depthai.Node) -> depthai.Pipeline

2. getParentPipeline(self: depthai.Node) -> depthai.Pipeline

property id

Id of node

property inputImage

Input image to be modified Default queue is blocking with size 8

property out

Outputs ImgFrame message that carries warped image.

setHwIds(self: depthai.node.Warp, arg0: List[int]) → None

Specify which hardware warp engines to use

Parameter ids:

Maximum frame size in bytes

setInterpolation(self: depthai.node.Warp, arg0: depthai.WarpProperties.Interpolation) → None

Specify which interpolation method to use

Parameter interpolation:

type of interpolation

setMaxOutputFrameSize(self: depthai.node.Warp, arg0: int) → None

Specify maximum size of output image.

Parameter maxFrameSize:

Maximum frame size in bytes

setNumFramesPool(self: depthai.node.Warp, arg0: int) → None

Specify number of frames in pool.

Parameter numFramesPool:

How many frames should the pool have

setOutputSize(*args, **kwargs)

Overloaded function.

1. setOutputSize(self: depthai.node.Warp, arg0: int, arg1: int) -> None

Sets output frame size in pixels

Parameter size:

width and height in pixels

2. setOutputSize(self: depthai.node.Warp, arg0: Tuple[int, int]) -> None

setWarpMesh(*args, **kwargs)

Overloaded function.

1. setWarpMesh(self: depthai.node.Warp, arg0: List[depthai.Point2f], arg1: int, arg2: int) -> None

2. setWarpMesh(self: depthai.node.Warp, arg0: List[Tuple[float, float]], arg1: int, arg2: int) -> None

class dai::node::Warp : public dai::NodeCRTP<Node, Warp, WarpProperties>

Warp node. Capability to crop, resize, warp, … incoming image frames.

Public Functions

Warp(const std::shared_ptr<PipelineImpl> &par, int64_t nodeId)

Warp(const std::shared_ptr<PipelineImpl> &par, int64_t nodeId, std::unique_ptr<Properties> props)

void setOutputSize(std::tuple<int, int> size)

Sets output frame size in pixels

Parameters

• size: width and height in pixels

void setOutputSize(int width, int height)

void setWarpMesh(const std::vector<Point2f> &meshData, int width, int height)

Set a custom warp mesh

Parameters

• meshData: 2D plane of mesh points, starting from top left to bottom right

• width: Width of mesh

• height: Height of mesh

void setWarpMesh(const std::vector<std::pair<float, float>> &meshData, int width, int height)

void setNumFramesPool(int numFramesPool)

Specify number of frames in pool.

Parameters

• numFramesPool: How many frames should the pool have

void setMaxOutputFrameSize(int maxFrameSize)

Specify maximum size of output image.

Parameters

• maxFrameSize: Maximum frame size in bytes

void setHwIds(std::vector<int> ids)

Specify which hardware warp engines to use

Parameters

• ids: Maximum frame size in bytes

std::vector<int> getHwIds() const

Retrieve which hardware warp engines to use.

void setInterpolation(Properties::Interpolation interpolation)

Specify which interpolation method to use

Parameters

• interpolation: type of interpolation

Properties::Interpolation getInterpolation() const

Retrieve which interpolation method to use.

Public Members

Input inputImage = {*this, "inputImage", Input::Type::SReceiver, true, 8, true, {{DatatypeEnum::ImgFrame, true}}}

Input image to be modified Default queue is blocking with size 8

Output out = {*this, "out", Output::Type::MSender, {{DatatypeEnum::ImgFrame, true}}}

Outputs ImgFrame message that carries warped image.

Public Static Attributes

static constexpr const char *NAME = "Warp"

Private Functions

void setWarpMesh(const float *meshData, int numMeshPoints, int width, int height)

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