Showing posts with label Machine Learning. Show all posts
Showing posts with label Machine Learning. Show all posts

Tuesday, December 24, 2019

Tuesday, May 22, 2018

Using deep learning and satellite imagery to improve land use classification in cities

Marta Gonzalez and colleagues have a recent paper using deep learning and satellite image data to improve land use classification. The authors have made documented code and Jupyter notebooks available here. I'm self recommitting the paper and code to my future self. HT Marco De Nadai.


Albert, A., Kaur, J., & Gonzalez, M. C. (2017, August). Using convolutional networks and satellite imagery to identify patterns in urban environments at a large scale. In Proceedings of the 23rd ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (pp. 1357-1366). ACM.


Abstact:
Urban planning applications (energy audits, investment, etc.) require an understanding of built infrastructure and its environment, i.e., both low-level, physical features (amount of vegetation, building area and geometry etc.), as well as higher-level concepts such as land use classes (which encode expert understanding of socio-economic end uses). This kind of data is expensive and labor-intensive to obtain, which limits its availability (particularly in developing countries). We analyze patterns in land use in urban neighborhoods using large-scale satellite imagery data (which is available worldwide from third-party providers) and state-of-the-art computer vision techniques based on deep convolutional neural networks. For supervision, given the limited availability of standard benchmarks for remote-sensing data, we obtain ground truth land use class labels carefully sampled from open-source surveys, in particular the Urban Atlas land classification dataset of $20$ land use classes across $~300$ European cities. We use this data to train and compare deep architectures which have recently shown good performance on standard computer vision tasks (image classification and segmentation), including on geospatial data. Furthermore, we show that the deep representations extracted from satellite imagery of urban environments can be used to compare neighborhoods across several cities. We make our dataset available for other machine learning researchers to use for remote-sensing applications.


Wednesday, November 29, 2017

Using deep learning and Google Street View to estimate the socioeconomic characteristics of neighborhoods

Timnit Gebru and her colleagues have recently published a very interesting paper in PNAS. The authors developed a method to analyze car images from Google Street View using machine-learning and computer vision methods to determine socioeconomic statistics and political preferences at the zip code level in the US. There is a video of Timnit Gebru presenting the paper here. 

Gebru, T., Krause, J., Wang, Y., Chen, D., Deng, J., Aiden, E. L., & Fei-Fei, L. (2017). Using deep learning and Google Street View to estimate the demographic makeup of neighborhoods across the United States. PNAS 2017 : 1700035114v1-201700035 [arxiv version here]

Abstract:
The United States spends more than $250 million each year on the American Community Survey (ACS), a labor-intensive door-to-door study that measures statistics relating to race, gender, education, occupation, unemployment, and other demographic factors. Although a comprehensive source of data, the lag between demographic changes and their appearance in the ACS can exceed several years. As digital imagery becomes ubiquitous and machine vision techniques improve, automated data analysis may become an increasingly practical supplement to the ACS. Here, we present a method that estimates socioeconomic characteristics of regions spanning 200 US cities by using 50 million images of street scenes gathered with Google Street View cars. Using deep learning-based computer vision techniques, we determined the make, model, and year of all motor vehicles encountered in particular neighborhoods. Data from this census of motor vehicles, which enumerated 22 million automobiles in total (8% of all automobiles in the United States), were used to accurately estimate income, race, education, and voting patterns at the zip code and precinct level. (The average US precinct contains ∼∼1,000 people.) The resulting associations are surprisingly simple and powerful. For instance, if the number of sedans encountered during a drive through a city is higher than the number of pickup trucks, the city is likely to vote for a Democrat during the next presidential election (88% chance); otherwise, it is likely to vote Republican (82%). Our results suggest that automated systems for monitoring demographics may effectively complement labor-intensive approaches, with the potential to measure demographics with fine spatial resolution, in close to real time.


cities used to train a model estimating socioeconomic data from car attributes 



Wednesday, November 2, 2016

The Impact of Urban Appearance


We have mentioned the work of Cesar Hidalgo (twitter) in this blog a few times already but he keeps coming up with new interesting research . As many will know, Hidalgo and his team have a project called Place Pulse, in which they use computer vision techniques to analyze snapshots of google street view and crowdsource people's perception on city’s physical appearance. Here are my three highlight of the project so far.


The research possibilities here are endless, so I'm sure I'll be posting updates on this project again in the future. Don't forget to input some of your own perceptions to the project.

Saturday, September 3, 2016

Using Computer Vision to Measure the Quality and Impact of Urban Appearance

Interesting paper on computer vision & urban economics, by Cesar Hidalgo and colleagues. Ungated version here.

Naik, N., Raskar, R., & Hidalgo, C. A. (2016). Cities Are Physical Too: Using Computer Vision to Measure the Quality and Impact of Urban Appearance. The American Economic Review, 106(5), 128-132.


Abstract
For social scientists, developing an empirical connection between the physical appearance of a city and the behavior and health of its inhabitants has proved challenging due to a lack of data on urban appearance. Can we use computers to quantify urban appearance from street-level imagery? We describe Streetscore: a computer vision algorithm that measures the perceived safety of streetscapes. Using Streetscore to evaluate 19 American cities, we find that the average perceived safety has a strong positive correlation with population density and household income; and the variation in perceived safety has a strong positive correlation with income inequality.