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")