IJP-JavaCV

IJP-JavaCV intends to help in working with OpenCV and JavaCV from JVM languages, like Scala. It is focused on working with ImageJ, but can be used without it.

Core functionality

Utilities for loading and displaying images using JavaCV
Helper for converting between OpenCV and Scala/Java constructs
API for conversion between ImageJ and OpenCV types
Color Chart Detector

ImageJ Plugins

Some of the functionality of OpenCV/JavaCV is exposed through ImageJ plugins

ColorChecker Detector
Hough Circles
Interactive segmentation using GrabCut algorithm

More information about plugins is in the Wiki

ImageJ Plugins Installation

Plugin binaries are provided on the Releases page

ImageJ Scription

All of OpenCV/JavaCV can be accessed from ImageJ through scripting. You can use any ImageJ scripting language, including Scala, JavaScript, Python (Jython). Intention of IJP-JavaCV is to make that scripting less verbose, proving utilities to make interaction with OpenCV API simpler.

Examples

Sample Scala scripts can be found in Examples-ImageJ.

Here is an example of a ImageJ's Scala script that is using CCheckerDetector (ColorChecker calibration chart detector):

import ij.IJ
import ij_plugins.javacv.IJOpenCVConverters.toMat
import ij_plugins.javacv.mcc.Utils.*
import org.bytedeco.opencv.global.opencv_mcc.*
import org.bytedeco.opencv.opencv_mcc.*

// Load image
val imp = IJ.openImage("data/IMG_0903_025p-crop.png")
if (imp != null) {
  imp.show()
  // ColorChecker detector requires RGB image as input
  val cp       = toColorProcessor(imp)
  // Convert RGB image to OpenCV representation
  val mat      = toMat(cp)
  // Create chart detector
  val detector = CCheckerDetector.create()
  // Detect chart and display chart outline as ROI
  if (detector.process(mat, MCC24)) {
    val checker = detector.getBestColorChecker
    imp.setRoi(toPolygonRoi(checker.getBox))
  } else
    IJ.showMessage("ColorChecker not detected")
} else
  IJ.noImage()

Additional Examples

Many examples of using OpenCV and JavaCV can be found in OpenCV Cookbook Examples project.

Use without ImageJ

The core functionality can be used as a library without ImageJ. You will need to add dependency on "net.sf.ij-plugins: ijp-javacv-core_3". For instance, for SBT:

libraryDependencies += "net.sf.ij-plugins" % "ijp-javacv-core_3" % version

Sample Scala scripts can be found in [Examples-CLI]. Here is an example of a ImageJ's Scala script that is using CCheckerDetector (ColorChecker calibration chart detector):

import ij_plugins.javacv.mcc.Utils.*
import ij_plugins.javacv.util.OpenCVUtils.*
import org.bytedeco.opencv.global.opencv_imgcodecs.IMREAD_COLOR
import org.bytedeco.opencv.global.opencv_mcc.*
import org.bytedeco.opencv.opencv_core.*
import org.bytedeco.opencv.opencv_mcc.*

import java.io.File

// We force loading as color image (IMREAD_COLOR), 
// as ColorChecker Detector expects only color images
val mat = loadAndShow(new File("data/IMG_0903_025p-crop.png"), IMREAD_COLOR)

// Create detector
val detector = CCheckerDetector.create()

// Detect chart and display tiles, if found
if (detector.process(mat, MCC24)) {
  // Get detected chart
  val checker = detector.getBestColorChecker

  // Draw detected tiles
  CCheckerDraw
    .create(checker, scalar(255, 255, 255), 1)
    .draw(mat)

  show(mat, "Detected ColorChecker tiles")
} else
  println("ColorChecker not detected")

ij-plugins / ijp-javacv 0.5.0