Shopachu – Incogna’s new visual product browser

Tuesday 5th January, 2010

In the back half of last year visual search outfit Incogna released their visual shopping browser Shopachu. I’ve followed some of Incogna’s previous releases so I thought I’d share some thoughts on this one too.

What does it do?

This site has a very similar model to our own consumer-facing MAST app; Empora. It makes money by sending consumers to retailer sites, who for obvious reasons are willing to pay for suitable traffic. The main forces that influence the design of a site like this are retention, and the clickthrough and conversion rates of your traffic:

Retention – you need to impress people, then ideally remind them to come back to you

Clickthrough – you need to send a good proportion of visitors to retailers in order to make money

Conversion – if the visitors you send aren’t interested in buying the clicked product then the retailers won’t want to pay for that traffic on a per-click basis (although they might be interested in the CPA model, which doesn’t pay until someone buys)

First Impressions

People’s first impressions are usually determined by a combination of design and how well a site conforms to their expectations. I’ve probably got distorted expectations considering my experience working with this type of application, but in that respect I was pleasantly surprised; Shopachu has some good features and makes them known. In terms of design I was less impressed, the icons and gel effects don’t seem to fit and I think there are whitespace and emphasis issues (sorry guys, trying to be constructive).

Finding stuff

It’s fairly easy to find things on Shopachu. The filters are easy to use (although I could get the brand filter to work, could be a glitch). The navigation is pretty easy, although it doesn’t currently provide second generation retail search features like facet counts (i.e. showing the number of products in a category before you click on it).

The biggest interesting technological problem I’ve noticed with their navigation is the colour definitions. There’s a big difference between a colour being present in an image, and the eye interpreting that colour as being present in an image. I think there are some improvements to be made in the way colours are attributed to images (e.g. here I’ve applied a pink filter but am seeing products with no pink returned). Similarly there’ll be another marked improvement with better background removal (e.g. here I’d applied a light blue filter and am seeing products with blue backgrounds).

Similarity search

Shopachu’s similarity search is quite different to Empora’s.  They’ve chosen to opt for maximum simplicity in the interface rather than user control, resulting in a single set of similarity search results. In contrast, Empora allows users to determine whether they’re interested in colour similarity, or shape similarity, or both. Simplicity often wins over functionality (iPod example #yawn) so it’ll be interesting to see how they do.

Another issue is the quality of the input data. This challenge is the same for Empora, or anyone else aggregating data from third parties, in that category information is inconsistent. One effect of this is that when looking at the similarity results for an often poorly-classified item like a belt you may also see jewellery or other items that have been classified as “accessories” or “miscellaneous” in the retailer’s data, another effect is that you often see duplicate items.

Keeping the traffic quality high

An interesting design decision for me is that the default image action on Shopachu is a similarity search, i.e when you click on the image it takes you to an internal page featuring more information and similar products. This is in contrast to the default action on Empora or, which is to send the visitor to the retailer’s product page.

The design trade-off here is between clickthrough and conversion rates. If you make it easy to get to the retailer your clickthrough rate goes up, but run the risk of a smaller proportion converting from a visit to a purchase. Here Shopachu are reducing that risk (and also the potential up-side) by keeping visitors on their site until they explicitly signal the intent to buy (the user has to click “buy” before they’re allowed through to the retailer).

Getting people hooked

There are a few features on Shopachu aimed at retention, namely Price Alerts and the ability to save outfits (Polyvore style). These features seem pretty usable, although I think they’re still lacking that level of polish that inspires passionate users. I’d be interested to know what the uptake statistics look like.

In summary

I think this implementation shows that Incogna have thought about all the right problems, and I think have clearly got the capability to solve the technological issues. On the down-side; cleaning up retailer’s data is a tough business which will be time-consuming, and I think they need to find a little inspiration on the visual design side.

Open Source Search Social

Thursday 5th November, 2009

It’s been a little while since the last Open Source Search Social, so we’re getting really imaginative and holding another one, this time on Wednesday the 18th of November. As usual the event is in the Pelican pub just off London’s face-bleedingly trendy Portobello Road.

The format is staying roughly the same. No agenda, no attitude, just some geeks talking about search and related topics in the presence of intoxicating substances.

Please come along if you can, just get in touch or sign up on the Upcoming page.

Guest post – Similarity search: The Two Shoe Problem

Thursday 30th July, 2009

Today I’m introducing my first ever guest post, written by Pixsta‘s own Rohit Patange about some great work he’s been doing with the guidance of Tuncer Aysal. You’ll be able to see the results of their work shortly on our consumer-facing site Empora. – RM

We at Pixsta are interested in understanding what is in an image (recognise and extract) and do so in an automated way that involves a minimum amount of human input.

Our raw data (images and associated textual information) come from a variety of retailers with considerable variation in terms of data formats and quality. Some retailer images are squeaky clean with white backgrounds and a clear product depiction while others have multiple views of the product, very noisy backgrounds, models, mannequins and other such distracting objects. Since we only care about the product, an essential processing step involves identification of all image parts and the isolation of individual products, if several are present in the retailer image.

The n-shoe case:

Let’s take the case of retailer images with multiple product views. This is most commonly encountered in shoe images.  Let us call each of the product views a ‘sub-image’.

When we talk about similar shoes we talk about a shoe being similar to the other (note the singular). We have to disregard how the shoe is presented in the image, the position of the sub-images, the orientation and other noise. If we do not do so, image matching technology tends to pick out images with similar presentation rather than similar shoes. Typically a retailer image (a shoe they are trying to sell) will have a pair of sub-images of shoes in different viewing angles. Pictorially with standard image matching we get the following results for a query image on the left:

Visual similarity query showing product presentation affecting results

Even though the image database contains images like:

Two shoes pointing to the right

These are not in the result set despite them being much closer matches, because of the presentation and varying number of sub-images.  To overcome this drawback, we have to extract the sub-image which best represents the product for each of the images and then compare these sub-images. For the sub-image to be extracted, the image will need to go through the following processing steps:

  • Determine which of the sub-images is the best represents the shoe.
  • Extract that sub-image.
  • Determine the shoe orientation in that sub-image.
  • Standardise the image by rotation, flipping and scaling.

All the product images (shoes in this case) go through this process of standardisation, resulting in a uniform set of images. Pictorially the input and the output image of the standardisation process are:

Shoes segmented and standardised to point right

Let’s look at the procedure in more detail assuming that the image has been segmented into background and foreground.

  • The first step is to identify all the sub-images on the foreground. The foreground pixels of the images are labelled in such a way that different sub-images have different label to mark them as distinct.
  • After the first iteration of labelling there is a high possibility that a sub-image is marked with 2 or more labels. Therefore all connected labels have to be merged.
    Segmented shoe images
  • The third step is to determine which of the sub-images is of interest; that is picking the right label.
    Choosing an image segment
  • Once the right sub-image is extracted the orientation of this sub-image is corrected to match a predefined standard to remove the differences in the terms of size of the product image, orientation (the direction the shoe is pointing towards) and the position of the shoe (sub-image) within the image.
    Single shoe pointing to the right

All product images (shoes in this case) go through this process before the representative information from the image is extracted for comparison. Now the results for the query image will look like:

Resulting query showing standardised similarity

Generally there are two shoes in an image. But the method can be extended to ‘n’ shoes.

Terminology, similarity search, and other animals

Thursday 30th April, 2009

In the walkway-level study room of my old Physics department there’s a desk, where I once found this timeless conversation etched into the surface like a prehistoric wooden version of Twitter:

Protagonist: – “You’re a mook”

Antagonist: – “What’s a mook?”

Protagonist: – “Only a mook would say that”

Aside from any revelations about the emotional maturity of undergrad physicists, I think the lesson here is that it speeds up comminucation if both parties use the same terminology and know what it means.

My area of the CBIR industry has a terminology problem. I’d like to have a vocabulary of terms to describe the apps that are emerging weekly.

Visual Search, Image Search, or Visual Image Search

We’re working on image search, of a sort, although the image isn’t necessarily the object of the search, nor does image search describe only CBIR-enabled apps. We’re searching using visual attributes of images, but “visual search” as a term has already been marked out by companies that visualise text search.

Similarity search

This one seems to hit the consumer-facing nail on the head, for some apps at least. Technologically I’d include audio search and image fingerprinting apps like Shazam and SnapTell in my term, but for consumers there may be no obvious connection so perhaps this is a runner.

Media As Search Term (MAST)

Media As SearchTerm describes for me the group of apps that use a media object such as an image or an audio clip as a search query to generate results, either of similar objects or of instances of  the same object. I think MAST sums up what I’d describe as my software peer group (media similarity and media fingerprinting apps), although it doesn’t seem as snappy as AJAX. Ah well.

Google Image Similarity first impressions

Tuesday 21st April, 2009

Right in line with my too-obvious-to-be-worth-anything prediction, Google have just released a Labs image similarity feature for Google Images. Others have commented on this already, but obviously this is hugely interesting for me because of my currently work on Empora‘s exploratory visual search so I’m going to throw my tuppence into the ring aswell.

Below are my first impressions.

Product impact

Google Similar Images (GSI) offers just one piece of functionality, the ability to find images that are similar to your selected image. You may only select images from their chosen set, there’s no dynamic image search capacity yet. Similar images are displayed either as a conventional result set when you click on “similar images”, or as a list of thumbnails in the header when you click through to see the original source.

The aims of this work will be (broadly):

  1. Keeping up with the Joneses. The other major search engines are working on similar functionality and Google can’t be seen to fall behind.
  2. User engagement. The more time you spend exploring on Google, the more their brand is burned into your subconscious.
  3. Later expansion of search monetisation. Adsense and Adwords get a better CTR than untargeted advertising because they adapt to the context of your search. If context can also be established visually there seems like strong potential for revenue.

Getting results

The quality of results for a project like this are always going to be variable as the compromises between precision, recall, performance, and cost are going to continue to be sketched out in crayon until more mature vocabularies and toolsets are available. That said, Google need to keep users impressed, and they’ve done pretty well.

A few good examples:

A few bad examples:

Under the hood

Once the “qtype=similar” parameter is set in the URL, the only parameter that affects the set of similar images is the “tbnid” which identifies the query image. The text query parameter does not seem to change the result set, only changing the accompanying UI. While this doesn’t allow us to draw any dramatic conclusions it would allow them to pre-compute the results for each image.

The first clear conclusion is metadata. Google have obviously been leveraging their formidable text index, and why not. The image similarity behaviour indicates that the textual metadata associated with images is being used to affect the results.  One of the clearest indicators is that they’re capable of recognising the same individual’s face as long as that person’s name is mentioned. Unnamed models don’t benefit from the same functionality.

My second insight is that they’re almost certainly using a structural technique such as Wavelet Decomposition to detect shapes within images. The dead give-away here is that search results are strongly biased towards photographs taken from the same angle.

I suspect that they’re not yet using a visual fingerprinting technique (such as FAST) to recognise photographs of the same object. If they were doing this already I suspect that they’d have used this method to remove duplicate images. This may well come later.


All in all my impression is that they’ve implemented this stuff well, but that there’s a lot more yet to come. Namely:

  • Handling of duplicates, i.e. separation between searching for the similar images and instances of the same image
  • A revenue stream

Empora walk-through

Wednesday 8th April, 2009

The first flight is always a little wobbly, and true to form there was a slight hiccup for Empora over the weekend. Still, it’s been live for a week now and is holding up well. Considering how

So now all the excitement of  the launch has settled down and we’re back into routine I think it’s time for a quick walk through the functionality (which won’t take that long since we haven’t put that much live yet; there’s a lot of interesting functionality left to come).

Hunting vs. gathering

Plenty of people go into a shop armed with a plan. They know what they want, or at least what specific need they need to fill. Others like to browse, look at what there is, what other people are doing, and generally wait for inspiration or recommendation. We’ve tried to fulfil both of those patterns using the both standard “search vs. browse” split, but have tried to improve both.


When you view an item, for example this orange Ghibli bag, we obviously show a picture, description, etc. and link to the retailer. All standard stuff for a shopping aggregator. What we’ve added is that we also show the most visually similar items in our collection, according to three different sets of criteria:

  1. We show the most similar bags by shape, so that anyone who’s interested in a particular style or type of bag can see them straight away.
  2. We show bags in the most similar colours, so anyone who was drawn to that bag because of its colour can see lots of other bags that they may also be interested in.
  3. We show products from other categories in the same colour, in case users want to colour-coordinate.


In addition to the regular search options you’d expect (category, keywords, etc.) we also allow people to search by the overall colour of the item (from the top right corner of any page). Now in terms of technology I’m not particularly happy with this functionality yet, but I’m a perfectionist. It already performs a lot better visually than the Amazon equivalent*, and I know that we’ve got big improvements in the pipeline.

* To be fair to Amazon their results are better than they look. The products they show are available in the query colour, they just choose to show only the first image, so their results look broken by visual inspection.

Back to the physical shop metaphor

What we’re trying to do is help the searchers search by enabling them to search using visual data, effectively the equivalent to training all the staff in a shop to be able to answer questions like “have you got anything that goes with these shoes?”.

At the same time we’re trying to help the browsers by sorting each department by type and colour, so they always know where they’re going.

Obviously this is fairly fresh territory so there’ll always be wrinkles that need ironing out, but on the whole I think the trend towards smarter indexing is inevitable, and the indexing of visual information is part of that (that’s a whole other post).

Search / Lucene social meet-up

Monday 6th April, 2009

Having just finished our product launch (apologies for the gratuitous plug) I’ve now got time to worry about more important things, i.e. organising beers.

We’ll be in The Pelican pub just near the Pixsta offices in Notting Hill from 7pm on the 27th of April. If you’re keen to come along and talk about Lucene, or search in general, then please do. There may also be talk of machine learning, computer vision, distributed systems, etc.

All I ask is that you sign up on the Yahoo event page so that I’ve got an idea about numbers (need to book tables, blah blah blah).