How to get a certain element out of an array within collection in MongoDB?

I have the following collection named 'CanvasCollection' in mongoDB and I want to get the image object with an id of "50e6fcc2edcbc10613000022" out of the array within this collection: 

{
"_id": ObjectId("50d1f440471ca84e1f000007"),
"image": [{
    "_id": ObjectId("50e6fcc2edcbc10613000022"),
    "type": "image",
    "filename": "50e6fcc2edcbc10613000022.jpg",
    "origname": "2811879134_7a57d7c586_m.jpg",
    "filepath": "upload/50e6fcc2edcbc10613000022.jpg",
    "thumbpath": "upload/50e6fcc2edcbc10613000022_small.jpg",)
}],
"text": [{
    "_id": ObjectId("50e6eda0edcbc1061300001b"),
    "content": "Type your text here"
}]
}

This doesn't seem to work:

CanvasCollection.find({'_id': new BSON.ObjectID('50d1f440471ca84e1f000007')}, {'image' : {$elemMatch: {'_id': new BSON.ObjectID('50e6fcc2edcbc10613000022')}}})

Any ideas how to get exactly this:

{
    "_id": ObjectId("50e6fcc2edcbc10613000022"),
    "type": "image",
    "filename": "50e6fcc2edcbc10613000022.jpg",
    "origname": "2811879134_7a57d7c586_m.jpg",
    "filepath": "upload/50e6fcc2edcbc10613000022.jpg",
    "thumbpath": "upload/50e6fcc2edcbc10613000022_small.jpg",)
}

If you have MongoDb version 2.2 you can do it like this:

db.CanvasCollection.aggregate({$project: {image:1}},{ $unwind : "$image" },{ $match : {"image._id": ObjectId("50e6fcc2edcbc10613000022")}})

(this is from mongo shell), output would be like this:

{
"result" : [
    {
        "_id" : ObjectId("50d1f440471ca84e1f000007"),
        "image" : {
            "_id" : ObjectId("50e6fcc2edcbc10613000022"),
            "type": "image",
            "filename": "50e6fcc2edcbc10613000022.jpg",
            "origname": "2811879134_7a57d7c586_m.jpg",
            "filepath": "upload/50e6fcc2edcbc10613000022.jpg",
            "thumbpath": "upload/50e6fcc2edcbc10613000022_small.jpg"
        }
    }
],
"ok" : 1
}

About unwind: http://docs.mongodb.org/manual/reference/aggregation/unwind/.

Similar topic: MongoDB extract only the selected item in array..

If you have older MongoDb version I think it's impossible.