Billing system and method thereof
Description
The present invention relates to a billing system and a
method thereof.
A billing system facilitates easy check out for customers
and the benefit is in the reduced checkout time because
stores are often able to efficiently run two to six
self billing units where it normally would have had one
cashier.
However, in most self billing systems the user has to
place the purchase items one by one thereby causing
delay. Further, the system is often unable to correctly
identify the items, or identifies items with low
confidence.
Conventionally, most of such systems cater to only the
products which are not packed in any bags. For products
packed in transparent bags, some conventional systems
involve preprocessing the image of the products for
removing the background, segmentation and histogram
analysis and matching in the HSI color space.
US 6668078 relates to segmenting an object from the
background of a scene. It captures an image of the
scene and the background. These images are processed
and compared on a pixel to pixel basis in the hue,
saturation and intensity domain.

It is an object of the present system to provide an
improved billing system.
The object is achieved by a billing system, comprising:
means for arranging purchase items and conveying the
arranged purchase items for identification;
imaging means for capturing an image of a portion of
the conveyed purchase item;
means for selecting multiple image sections from the
captured image;
means for identifying the purchase item using each of
the image sections as input and analyzing the image
sections with respect to features usable for
identifying the purchase item; and
means for billing the identified purchase item.
The object is achieved by a method for billing,
comprising:
arranging purchase items and conveying the arranged
purchase items for identification;
capturing an image of a portion of the conveyed
purchase item;
selecting multiple image sections from the captured
image;
identifying the purchase item using each of the image
sections as input and analyzing the image sections
with respect to features usable for identifying the
purchase item; and
billing the identified purchase item.
The underlying idea of the present invention is to
provide a billing system which does not need user
intervention. The system captures images of only a
portion of the purchase item, which does not contain the

background. Further, only some sections of the image are
used for recognition of the purchase item. This removes
the step of processing and segmentation of the images,
usually used while recognition. Also it assures no user
interference.
In an embodiment, the means for arranging and conveying
the purchase items comprise a plurality of blades for
arranging the purchase items linearly and a conveyor belt
for conveying the linearly arranged purchase items to the
imaging means for identification of the purchase items.
The embodiment of the invention automates the movement of
the purchase item through a conveyor belt. The belt has
blades by which the purchasing items moving on the belt
are arranged linearly when they encounter the blades.
Hence the purchase items do not need to be handled one by
one manually for identification.
In another embodiment, the imaging means comprises a
glass panel for receiving the purchase items conveyed by
the conveyor belt, illuminating means for illuminating
the purchase item placed on the glass panel and means for
capturing an image of an illuminated portion of the
purchase item. The purchase items packed in transparent
bags cause some spurious reflections thus leading to
erroneous recognition. Hence according to the embodiment
of the invention the purchase items are kept on a glass
panel and an illuminating means is arranged on looking
the purchase item from the bottom of the glass panel.
This increases the surface area of the polythene bag
which is aligned perpendicular to the incident light and
reduces reflection. The image capturing means receives
light reflected solely from the bag contents. Thus the
background is avoided. It captures images of the purchase

item from below the glass panel and sends it for
processing and identification.
In yet another embodiment, the means for selecting
multiple image sections comprise means for converting the
captured image to a chromatic color space and means for
selecting multiple image sections from the captured image
having a desired chromatic content value. The embodiment
of the invention uses hue and/or saturation value of the
images and rejects intensity value for eliminating
variations in lighting and focuses more on the color
content. For extracting hue and saturation value, the
present color space of the images is usually converted to
hue, saturation, intensity (HSI) color space. The
chromatic content value is extracted from here, which is
used for identification.
In yet another embodiment, the means for identifying
comprise detection means for detecting the purchase item
using the chromatic content value and a texture
information of the image section. The present invention
uses a recognition algorithm which accepts as input the
image section and identifies the purchase items using the
chromatic content value and a texture information of the
image sections.
In yet another embodiment, the billing system comprises
means for weighing the purchase item placed on the glass
panel. The weight of the purchase item is used for
billing the purchase item, when the item is sold by
weight. In another embodiment, the weight is used for
identification of the purchase item.

The present invention is further described hereinafter
with reference to illustrated embodiments shown in the
accompanying drawings, in which:
FIG 1 shows a block diagram of the billing system as per
an embodiment of the present invention,
FIG 2 shows the imaging and the recognition system of the
present invention,
FIG 3 shows the working of the imaging system of the
present invention, and
FIG 4 shows a flowchart describing the recognition of the
purchase items.
In a preferred embodiment, the present invention
comprises a linearizing mechanical system. It arranges
the purchase items of a user in a line and sends them for
identification. FIG 1 shows the block diagram of the
present, invention along with the linearizing mechanical
system. In one embodiment, paddle blades 12 are utilized
to convert a randomized set of purchase items into an
organized linear flow that can be used conveniently for
identification of the purchase item and billing.
The linearizing mechanical system starts with a cast
point 10 where a user casts the purchase item. In one
embodiment, purchase items packed in transparent bags are
cast at the cast point 10. A conveyor belt 11 conveys the
purchase item from the cast point 10 to a glass panel 13
for identification.

In an embodiment, the conveyor belt 11 has a series of
paddle blades 12 for arranging the purchase items in a
linear manner. The conveyor belt 11 carrying the purchase
items moves below the blades 12. As the objects on the
conveyor belt encounter each blade, they get arranged in
a linear manner.
The linearly arranged purchase items reach one by one to
a glass panel 13. The glass panel 13 has means for
capturing images of the purchase item reaching it through
the conveyor belt 11. The captured images are sent to
identification means 14 which processes the images and
identifies the purchase item. Hence all user intervention
is avoided.
In one embodiment, in case of a low confidence
recognition, the present invention transmits a video of
the purchase item being recognized to an attendant.
FIG 2 describes the working of the imaging system and the
identification system of the present invention.
The purchase items are conveyed by the conveyor belt 11
to the transparent glass panel 13 as described above. In
an embodiment, the imaging system of the present
invention includes an enclosure to prevent ambient
lighting. An illuminating means 21 is provided below the
glass pane 13. The enclosure ensures consistent lighting
by the illuminating means 21. For purchase item sold by
weight 20, the items are packed in a transparent bag like
polythene bag. The use of polythene bag causes some
spurious reflection thus reducing the detection ability
of the present invention. Therefore the illuminating
means are arranged on looking the purchase item from

below the glass panel. This increases the surface area of
the polythene bag receiving the incident light thereby
reducing spurious reflections. A camera 22, also arranged
below the glass panel, captures the image of the
illuminated portion of the purchase item.
This arrangement of the imaging system makes the camera
22 receive light reflected only from the bag contents 20.
Thus the background is avoided and processing and
recognition is faster.
The captured images are sent by the camera for
identification. The identification means processes the
images at the processing and detecting means 23. The
identification of the purchase item is described in
detail in FIG 4.
The identification means has output means 12 and 12a. The
details of the purchase item which are identified, are
provided as output. In an embodiment, the output means 12
displays all images and results through a display means.
An attendant may interrupt only for cases of low
confidence identification. The output means 12a shows the
item type, weight and the billing amount to the user.
Thus the shown embodiment of the present invention
enables self checkout for users and needs attendant
interference only for low confidence identification.
FIG 3 describes the process of image acquisition of the
purchase item.
In one embodiment, the present invention comprises an
enclosure to prevent ambient lighting during recognition.

For the process of image acquisition at step 31, the
invention uses an arrangement such that the image has
negligible background. In step 32, the purchase item is
kept over the glass panel. It is illuminated from below
the glass panel so the light is incident on the glass, in
step 33. This incident light is reflected by the contents
kept over the glass panel. In step 34, the camera
receives light reflected only from the bag contents,
which makes the recognition easy. Thus a image with
negligible background signature is achieved in step 35.
FIG 4 describes the working of the recognition system of
the present invention.
In an embodiment, the images of the purchase item
captured by the camera in step 41 are sent to a
processing means for identification. The simplicity in
the recognition method is achieved by using a rectangular
section of the total image captured. This section
cropping is done in step 42. In one embodiment, the image
sections are selected based on the chromatic content and
texture. The selected and extracted image sections are
together provided as input to a recognition algorithm in
step 43. In one embodiment, RBF kernel based support
vector machine SVM recognition algorithm is used. The SVM
is trained with patches manually extracted from images of
various purchase items.
In step 44, the output given by each of the input image
sections, for a particular image section, are clustered.
In one embodiment, a majority vote of the prediction
result from each image section is used to give a final
output in step 45. The final result is displayed and used
for billing.

Although the invention has been described with reference
to specific embodiments, this description is not meant to
be construed in a limiting sense. Various modifications
of the disclosed embodiments, as well as alternate
embodiments of the invention, will become apparent to
persons skilled in the art upon reference to the
description of the invention. It is therefore
contemplated that such modifications can be made without
departing from the spirit or scope of the present
invention as defined.

We claim:
1. A billing system, comprising:
means for arranging purchase items and conveying
the arranged purchase items (11,1.2) for
identification;
imaging means for capturing an image of a portion
of the conveyed purchase item (13);
means for selecting multiple image sections from
the captured image (14);
means for identifying the purchase item using each
of the image sections as input and analyzing the
image sections with respect to features usable for
identifying the purchase item (14); and
means for billing the identified purchase item
(12a).
2. The billing system according to claim 1, wherein the
means for arranging and conveying the purchase items
comprise:
a plurality of blades (12) for arranging the
purchase items linearly; and
a conveyor belt (11) for conveying the linearly
arranged purchase items to the imaging means for
identification of the purchase items.
3. The billing system according to any of the preceding
claims, wherein the imaging means comprises:
a glass panel (13) for receiving the purchase
items conveyed by the conveyor belt;

illuminating means (21) for illuminating the
purchase item placed on the glass panel; and
means for capturing an image (22) of an
illuminated portion of the purchase item.
4. The billing system according to any of the preceding
claims, wherein the means for selecting multiple
image sections comprise:
means for converting the captured image to a
chromatic color space (23); and
means for selecting multiple image sections from
the captured image having a desired chromatic
content value (23).
5. The billing system according to claim 4, wherein the
means for identifying comprise detection means for
detecting the purchase item using the chromatic
content value and a texture information of the image
section (23).
6. The billing system according to any of the preceding
claims comprising means for weighing the purchase
item placed on the glass panel.
7. A method for billing, comprising:
arranging purchase items and conveying the
arranged purchase items for identification;
capturing an image of a portion of the conveyed
purchase item (41);
selecting multiple image sections from the
captured image (42);

identifying the purchase item using each of the
image sections as input and analyzing the image
sections with respect to features usable for
identifying the purchase item (43); and
billing the identified purchase item (45).
8. The method according to claim 7, wherein the step of
arranging and conveying the purchase items
comprises:
arranging the purchase items linearly using a
plurality of blades; and
conveying the linearly arranged purchase items to
the imaging means for identification of the
purchase items using a conveyor belt.
9. The method according to any of claims 7 or 8,
wherein the step of capturing an image comprises:
receiving the purchase items conveyed by the
conveyor belt at a glass panel (32);
illuminating the purchase item placed on the glass
panel (33) ; and
capturing an image of an illuminated portion of
the purchase item (34).
10. The method according to any of claims 7 to 9,
wherein the step of selecting multiple image
sections comprises:
- converting the captured image to a chromatic color
space; and

selecting multiple image sections from the
captured image having a desired chromatic content
value.
11. The method according to claim 10, wherein the step
of identifying comprises detecting the purchase item
using the chromatic content value and a texture
information of the image section (43).
12. The method according to any of claims 7 to 11,
comprising weighing the purchase item placed on the
glass panel.
13. A system or method substantially as herein described
and illustrated in the figures of the accompanying
drawings.

The present invention relates to a billing system
comprising means for arranging purchase items and
conveying the arranged purchase items for identification;
imaging means for capturing an image of a portion of the
conveyed purchase item, means for selecting multiple
image sections from the captured image, means for
identifying the purchase item using each of the image
sections as input and analyzing the image sections with
respect to features usable for identifying the purchase
item, and means for billing the identified purchase item.