Documentation
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Overview ¶
Package calib converts between camera-frame 3D coordinates (millimetres) and image pixel coordinates using pinhole intrinsics.
The math mirrors the vendor SDK's stereoConvetPoint3dToDepth / stereoConvetDepthToPoint3d (libStereoCamera.so, Huaray/Dahua 5000 series): pure pinhole projection without distortion, rescaled from the calibration resolution to the actual output resolution by the width ratio only:
scale = intrinsicImgWidth / imgW u = (x*K[fx]/z + K[cx]) / scale v = (y*K[fy]/z + K[cy]) / scale
Points are expected in the target camera's own frame: origin on the optical axis, X right, Y down, Z forward along the optical axis (millimetres).
Index ¶
Constants ¶
const ( FX = 0 FY = 4 CX = 2 CY = 5 )
Indices into the row-major 3x3 intrinsic matrix { fx, 0, cx, 0, fy, cy, 0, 0, 1 }.
Variables ¶
var ErrNoCalib = errors.New("calib: camera calibration bank is empty")
ErrNoCalib is returned when the camera reports an empty calibration bank (device shipped without on-camera calibration).
Functions ¶
func ReadCalibTypes ¶
func ReadCalibTypes(p RegisterPort) ([]string, error)
ReadCalibTypes returns the calibration type names the camera reports in bank 0x20000 (semicolon-separated, e.g. "calibration_pd").
Types ¶
type CamCalib ¶
type CamCalib struct {
// IntrinsicImgWidth/Height is the resolution the intrinsics were
// calibrated at. Projections onto other resolutions are rescaled by the
// width ratio, matching the vendor SDK.
IntrinsicImgWidth int
IntrinsicImgHeight int
// K is the row-major 3x3 intrinsic matrix { fx, 0, cx, 0, fy, cy, 0, 0, 1 }.
K [9]float64
}
CamCalib holds the pinhole intrinsics of one image type.
func (CamCalib) DeprojectPixel ¶
DeprojectPixel back-projects a pixel plus depth (mm) to a camera-frame point. It is the exact inverse of ProjectPoint3D.
type RegisterPort ¶
type RegisterPort interface {
ReadReg(addr uint32) (uint32, error)
WriteReg(addr, value uint32) error
ReadMem(addr uint32, n int) ([]byte, error)
}
RegisterPort is the register-level transport needed to read camera memory banks. *gvcp.GVCP implements it.
type StereoCalib ¶
type StereoCalib struct {
LeftImgW, LeftImgH int
LeftK [9]float64 // leftCamIntrinsic @0x008
LeftDistortion [12]float64 // leftCamDistortion @0x050
RightImgW, RightImgH int
RightK [9]float64 // rightCamIntrinsic @0x0B8
RightDistortion [12]float64 // rightCamDistortion @0x100
LeftToRightExtrinsic [16]float64 // @0x160
LeftRectifyR [9]float64 // @0x1E0
RightRectifyR [9]float64 // @0x228
LeftP [12]float64 // @0x270
RightP [12]float64 // @0x2D0
Q [16]float64 // disparity-to-depth matrix @0x330
LeftValidRoi [4]int32 // @0x3B0
RightValidRoi [4]int32 // @0x3C0 (never serialized by the vendor JSON)
StereoRmsError float64 // @0x3D0
AveEpipolarError float64 // @0x3D8
ColorImgW, ColorImgH int
ColorK [9]float64 // colorCamIntrinsic @0x3E8
ColorDistortion [12]float64 // colorCamDistortion @0x430
RectLeftToColorExtrinsic [16]float64 // @0x490
RectRightToColorExtrinsic [16]float64 // @0x510
LeftToColorRmsError float64 // @0x590
RightToColorRmsError float64 // @0x598
ColorRmsError float64 // @0x5A0
}
StereoCalib mirrors the vendor MvSstereoCalibrateResult POD (1600 bytes, little-endian) stored in camera memory bank 0x20001. Field offsets were recovered from CalibFile::struct2Json and cross-checked against a real DS5131MG30CE calibration export.
func ReadStereoCalib ¶
func ReadStereoCalib(p RegisterPort) (*StereoCalib, error)
ReadStereoCalib downloads the stereo/color calibration from the camera's memory bank 0x20001 over GVCP, verifying the vendor CRC32.
func (*StereoCalib) Color ¶
func (s *StereoCalib) Color() (CamCalib, error)
Color returns the color-camera intrinsics.
func (*StereoCalib) Left ¶
func (s *StereoCalib) Left() (CamCalib, error)
Left returns the raw left (IR) camera intrinsics.
func (*StereoCalib) RectifiedLeft ¶
func (s *StereoCalib) RectifiedLeft() (CamCalib, error)
RectifiedLeft returns the rectified-left projection P as cam calib. Volume results are computed on rectified images, so pack centres are most often in this frame.
type VendorCalibJSON ¶
type VendorCalibJSON struct {
CameraCalib struct {
ColorCamImgWidth int `json:"colorCamImgWidth"`
ColorCamImgHeight int `json:"colorCamImgHeight"`
ColorCamIntrinsic []float64 `json:"colorCamIntrinsic"`
LeftCamImgWidth int `json:"leftCamImgWidth"`
LeftCamImgHeight int `json:"leftCamImgHeight"`
LeftCamIntrinsic []float64 `json:"leftCamIntrinsic"`
LeftP []float64 `json:"leftP"`
WorkDistance float64 `json:"WorkDistance"`
} `json:"CameraCalib"`
}
VendorCalibJSON mirrors the calibration export written by the vendor tools ("IPC4.94 Camera Calibration.json" style): a top-level CameraCalib object with per-camera intrinsics and resolutions.
func LoadVendorFile ¶
func LoadVendorFile(path string) (VendorCalibJSON, error)
LoadVendorFile reads a vendor calibration export from path.
func (VendorCalibJSON) Color ¶
func (v VendorCalibJSON) Color() (CamCalib, error)
Color returns the color-camera intrinsics from a vendor calibration export.
func (VendorCalibJSON) Left ¶
func (v VendorCalibJSON) Left() (CamCalib, error)
Left returns the raw left (IR) camera intrinsics from a vendor export.
func (VendorCalibJSON) RectifiedLeft ¶
func (v VendorCalibJSON) RectifiedLeft() (CamCalib, error)
RectifiedLeft returns the rectified-left projection P as cam calib. Volume results are computed on rectified images, so pack centres are most often in this frame; P has the form { fx', 0, cx', 0, fy', cy', ... }.
Source Files