Image Occlusion addon
Occlusion 2.0 User Manual
This addon allows you to add image
occlusion cards to Anki. Image occlusion cards are like cloze deletions
In general, you hide parts of an image, and during the repetitions you
must guess what the hidden part is.
Image Occlusions are discussed in the esupermemo website (www.supermemo.com/articles/flow.htm#Occlusion
In practice, you will often have an image with labels, and you will
hide the labels which you want to guess during the repetitions. Because
an image is worth 1000 words (this are just one of 38 cards generated
at once from the original image):
The addon is very simple. In the note editor
, a new button has
appeared, containing the text Image
(ignore the cute panda, the lightning bolt icon and the grey snowflakes
near the fields; they are from some of my other addons. If you are
curious, please see check these: panda
, lightning bolt
To add new Image Occlusion cards to your collection, click that button.
You will be asked to choose an image file to generate cards from it.
Choose the file, and a new window will appear, with an image editor
containing the image ready for you to edit. You generate Image
Occlusion cards by drawing shapes (or masks) over the original image.
There are several shapes you can draw, and you can group shapes
together to cover non-contiguous parts of the image. In the vast
majority of cases you will want to use rectangles.
Let's see how everything is processed from the begining:
Step by Step
Open the note editor (by clicking Add
in the deck browser, for example)
Click the Image Occlusion button
An image editor will appear.
Besides showing the editing area, the current version allows you to
supply (optionally, of course):
- Header: is shown above
the images when studying
- Footer: is shown below
the image when studying
- Tags: are added to the
notes. This is how you supply tags to the Image Occlusion cards.
Changing the tags in teh note editor doesn't affect the tags of the
Image Occlusion cards.
You can also select the deck
to which your cards will be added, by clicking the button at the
bottom. This button works just like the Choose Deck dialog in the Anki
These images don't show these features because they are from the
previous version. They have not been updated due to lack of
You can now start to draw rectangles
over the labels you want to hide in your image.
The initial tool is the rectangle tool, so you can start
drawing rectangles right away. The rectangles are initially set to
white, but the color can be changed in the color panel in the bottom of
the screen. The rectangle tool is marked with an arrow in the following
Repeat for all labels
that all labels are hidden, you must add the cards to Anki. To add the
cards, you click one of the following buttons (their meaning will be
A tooltip will appear telling you how many cards have been added.
Congratulations: you have added your first image occlusion note.
of the buttons
There are two buttons:
(Mnemonic: notice that
two shapes don't overlap)
||(Mnemonic: notice that
two shapes overlap)
This button is called non-overlapping
because it generates cards in which there is no overlapping information.
This is because the question side of the cards hides all labels, hiding
the label the user is supposed to guess in a different color, and the
answer shows only that layer (and none of the other layers). This is
the same as showing a cloze deletion sentence with all parts hidden,
while asking only for one of them. For example:
This button is called overlapping
because it generates cards in which there is overlapping information.
is because the question side of the cards shows all labels except
for the one the user is supposed to guess, and the answer shows all
labels. This is the same as showing a cloze deletion sentence with only
one cloze for the user to guess. For example (compare with the
one do I use?
That depends on the material you're
adding, as wel as your personal preferences.
I believe that for images that consist of a drawing with some labels
pointing to parts of the image, non-overlapping
image oclcusion is better, because it deprives the user of clues that
might help him to answer the answer correctly without being really
sure. A user that can see all labels except for one might easily be
able to guess the missing one. Despite this conjecture, I have no data
showing the superiority of either method in this situation.
In images where context is critical, like a diagram representing a
biochemistry cycle (e.g. Krebs cycle), in chich the compounds come one
after the other, you have to use overlapping
image occlusion. You can't guess the that a label is hiding compound B
, for example, unless you can see
that it comes from A
Here is an example of overlapping image occlusion being used on a
diagram of the Krebs
With non-overlapping image occlusion you
would have to memorize the
place of fumaric acid in this specific drawing of the cycle. With
overlapping image occlusion, you have only to memorize which compound
comes from succinic acid and
turns into malic acid, which
is exactly our goal.
Adding Images from
If you have an image in the clipboard (a
screenshot, for example), when you click the Image Occlusion
button, the addon will not ask you for a filename, and will use the
image in the clipboard. The image will be cleared from the clipboard
imediately after appearing in the image editor. If clearing the
clipboard is inconvenient for you, drop me a line and I will make this
Although the previous discussion used
rectangles as an example, you can
use any kind of shapes, or even a group of shapes to hide parts of the
image. Using a group of shapes might be useful if you want to hide two
non contiguous parts of the image. See this
for a turorial on the use of the editor, which includes
instructions on how to group/ungroup objects.
Here is an example of using a group of two rectangles to hide two
different chemical compounds in the Krebs cycle:
Why do I choose to hide them at the same time? Well, anyone who knows
some biochemistry knows that if you see NAD+ in one side of a chemical
reaction, NADH will appear on the other side (not always, but
incredibly often in human metabolism). If you are shown one of them,
guessing the other requires no knowlege of the specific chemical
reaction you are studying. We want to test our knowlege of the Krebs
cycle, and not whether or not we know a basic rule of thumb, and so we
hide both compunds at the same time. Because these two compounds are so
closely associated at this stage (to understand the Krebs cycle you
need to know
, namely what NAD+ and NADH are), the pair works as a
and we are not contradicting the minimum
the image before placing the masks
You can edit the image to before hide
the masks. The editor contains a side panel named layers. If you click
the word layers, it will appear. By default, the Shapes
layer is active, which means
that whatever you draw is interpreted as a mask to hide part of the
However, if you select the Picture
layer (by clicking it), you will be able to draw over the image in a
way that is not interpreted as masks hiding the image. When you want to
draw the masks, you just select the Shapes
As of the current version, you can
the default color of the rectangles in the editor [default
value is white]. Please note that you can also change the rectangle
color in the editor itself.
the color of the
rectangle that appears in the question [default value is red, as in the
examples shown]. You can't change this option in the editor.
To change configure this options, go to
> Image Occlusion 2.0 (options)
as shown in the picture:
The following window will appear:
Click the Choose Color
buttons, and you will be presented with a color palette from which you
can choose a color.
You can access this help from the help
menu of Anki's main window:
for the future
Being able to update image occlusion
notes, while preserving some of the review history.
Suggestions are accepted and deeply appreciated.
this editor you're using?
that is available in the official
. None of the core code has been touched, and only an
extension has been written.
Where is the place to go to know more
about this editor?
You can go to the official website
contains lots of documentation, and can give you ideas on
how to use the full power of svg-edit to your image occlusion workflow
(I have to say that in my opinion most of the time nothing beats the
old rectangle). This
is also very helpful.
editor refuses to
appear correctly. Why?
Please make sure you have the most
current version of the addon, which is "Image Occlusion version 2.1",
as indicated in the ankiweb
Can I add images from the clipboard?
I have another question!
Contact the author: firstname.lastname@example.org