Chicken weighed by image

Calculating the carcass weight by filming improves industrial poultry production

Brazil’s chicken industry, whose organization and technology in genetics, nutrition and processing now qualify it as one of the biggest and most advanced in the world, can now rely on a system for assessing weight by video camera. The system advances by one hour the programming of the flow of production and organizes the process. Created by a small company called Unisoma Matemática para Produtividade, as part of a project for controlling production at abattoirs, the system helps to program the flow, right from the arrival of the chickens at the abattoir to the final procedures of packaging and distribution. Based in Campinas, the company has among its customers the Companhia Vale do Rio Doce, pulp and paper factories and agroindustries. Its president, Miguel Taube Netto, reveals that the project for weighing by computer vision is a by-product of the system called Integrated Planning for the Production of Poultry (PIPA), developed between 1989 and 1997, and implemented in the productive chain of the Sadia group.

PIPA consists of modules that are based on mathematical and statistical techniques and link together the processes along the chain – which goes from the production of breeding grandmother hens and one-day chicks to the housing for the chicks, their nutrition, growth, the system for collecting them from the poultry farmer, their delivery to the packing station, slaughter, classification, packaging and distribution.

In the course of ten years, Unisoma has implanted in Sadia various modules for the planning and control of the activities, involving the slaughter of more than 6,000 batches, and each batch has 12,000 chickens. This has led to the average daily slaughter of more than 1 million chickens, over 300 products differentiated by weight range and kind of cut, the allocation of production in seven abattoirs in accordance with the specialization of each one, and distribution over various sales regions in Brazil and abroad. Thanks to PIPA, Taube says, Sadia achieved gains of US$ 50 million between 1992 and 1994, due to improved conversion of foodstuffs and to the choice of products with higher profit margins.

Focus on the back
Assessing weight on the production line works with a video camera coupled to an image treatment board and a computer with specific software. The camera captures the image in movement – at a speed of three birds a second – and the computer does an estimate of weight, based on the area of the back. “As there is a relatively constant relation between size and weight in poultry, the system captures the image of each carcass, extracts its dimensions, and, on the basis of regression equation , estimates the weight, providing as a result a histogram (graph of frequencies) of the distribution of the weights of the birds at every moment”, says Taube.

According to Ricardo Mayer de Aquino, an electrical engineer with a grant from the National Council of Scientific and Technological Development (CNPq) who is responsible for the development and implementation of the project, the system’s margin of error is 5%. “At first, we tried to use the outline of the chicken in the area of the thigh and wing, but we later came to the conclusion that the area that bears most relation to the weight of a chicken is its back”, says Roberto de Alencar Lotufo, of the Faculty of Electrical Engineering of the University of Campinas (Unicamp), a consultant for the project and responsible for the software. He explains: The computer captures the image, identifies the area of the back, does the calculation and converts it into weight”.

Mathematical decisions
Under the usual method, weighing takes place after the carcass is cooled – because, after slaughter, the chicken goes to the cooling hung on hooks that do not allow weighing. Once slaughtered, plucked and without viscera, the chickens are inspected and dropped into the cooling tank, where they are washed for one hour in chlorinated and filtered water, at 5°C. Afterwards, hung by one leg, they follow along a rail and are weighed by an electromechanical process: the weight is captured by a computer, which classifies the birds by category and forwards them for processing.

Only then is it decided, by the category of weight, to which product range the carcasses should actually go: whole chicken, chicken in cuts, and others. Whole chicken has various destinations: the ultralight, between 950 and 1,050 grams, goes to Arab countries, while the heavier ones are sold, whole, in the domestic market, or are exported in cuts. Calculating weight by image, though, before cooling, makes it possible to program this classification 1 hour earlier, to comply with the daily production plan. “Weighing before cooling allows the programmer who classifies the chickens at the packing station to make decisions that are mathematically structured for the planning of the day”, says Taube. In addition, the method has proved to be more economical and to interfere less in the process.

The calculation is more precise than the first weighing – which takes place when the chickens are still alive, in the trucks, often with their feathers wet. The new method also contributes towards monitoring the performance of the poultry farmers and to controlling the weight profile of each batch that arrives at the abattoir. And it can even help in controlling the water absorbed during cooling.

Last February, the team monitored a prototype at the Pena Branca packing station in the city of Amparo, in the Campinas region, and tested changes in the position of the camera and in the lights. The packing station slaughters 130 chickens a minute and 3 million a month – half are whole chickens and half are for cuts – and exports about 500 tons a month to Saudi Arabia. Engineer Luiz Bonetto, who is responsible for technology at the packing station, has words of praise: “As the weight of a chicken varies from 800 grams to 3 kilograms, the system makes possible a more precise programming in the classification and packaging room, since the poultry farmer does not always send the expected weight”.

Businessman Taube reveals that, once its development is finished, the prototype will be installed in Sadia’s plant in Toledo, Paraná, which has three slaughter lines. For Taube, an aeronautical engineer with a doctor’s degree in industrial engineering and head of Applied Mathematics at Unicamp, “the approval of the prototype shows that there is a great market for the system”. He estimates this market at 30 abattoirs in Brazil and another 200 abroad. He intends to sell the weighing system for US$ 25,000. The complete system, though, like PIPA, can cost more than US$ 1 million. This is a broad perspective for Unisoma, which has 12 employees, grosses U$ 500,000 a year, and has been working with innovations since it was founded in 1984.

The best in the sector – Taube points out that Brazil is the second largest exporter of chicken meat, after the United States: out of a production of 5.7 million tons of meat last year, which corresponds to 2.5 billion birds, 906,000 tons were exported, according to the Association of Producers for Chicks for the Table (Apinco). For Taube, the United States may export more, but “the Brazilian industry is more sophisticated, since it works with hundreds of products intended for the domestic and foreign markets, which buy whole chickens of various weights, divided by category, and cut into parts, with and without bones, and giblets”. Even the feet of the chicken are exported, to Asia. However, the critical point in the productive chain is the control over the daily production at the abattoirs, due to the great variation in the weight of the birds and to the variety of products – hence the relevance of the project.

The Project
Control of Daily Production at Chicken Abattoirs (nº 97/07444-7); Modality Program for Technological Innovation in Small Companies (PIPE); Coordinator Miguel Taube Netto – Unisoma; Investment R$ 170,460.00