如何在R中提取灰度图像的像素颜色

Question

我想知道如何使用R上的图形创建一个带有像素颜色信息的矩阵。在示例中，我们的想法是将灰度图像处理为这样的矩阵：

     [,1]    [,2]    [,3]   
[1,] "Black" "White" "Black"
[2,] "White" "Black" "White"
[3,] "Black" "White" "White"

Answer 1

您可以使用insert into zipcode values (98225, 'Bellingham', 'WA'); insert into zipcode values (95388, 'Winton', 'CA'); insert into zipcode values (44242, 'Stow', 'OH'); insert into zipcode values (61536, 'Hanna city', 'IL'); insert into zipcode values (01254, 'Richmond', 'MA'); insert into zipcode values (95124, 'San Jose', 'CA'); insert into zipcode values (95382, 'Turlock', 'CA'); insert into zipcode values (95380, 'Turlock', 'CA'); insert into zipcode values (98102, 'Seattle', 'WA'); insert into employee values ('P0239401', 'Jones Hoffer',98225, '2000-12-12'); insert into employee values ('P0239402', 'Jeffrey Prescott',95388, '2016-11-07'); insert into employee values ('P0239403', 'Fred NcFaddeb',95124, '2008-09-01'); insert into employee values ('P0239404', 'Karen Ives',98102, '2014-05-21'); insert into book values (10501, 'Forensic Accounting',200, 229.99); insert into book values (10502, 'SAP Business One',159, 149.99); insert into book values (10503, 'Fraud Cases',190, 179.99); insert into book values (10504, 'CPA Review',65, 279.99); insert into book values (10605, 'Quickbooks for Business',322, 59.99); insert into book values (10704, 'Financial Accounting',129, 164.99); insert into book values (10879, 'Managerial Accounting',155, 114.99); insert into book values (10933, 'Cost Accounting',122, 219.99); insert into book values (10948, 'Intermediate Accounting',123, 164.99); insert into book values (10965, 'Accounting Information Systems',211, 259.99); insert into book values (10988, 'XBRL in Nutshell',124, 109.99); insert into customer values (23511, 'Michelle Kuan', '123 Main St.',98225, '360-636-5555'); insert into customer values (23512, 'George Myer', '237 Ash Ave.',95124, '312-678-5555'); insert into customer values (23513, 'Richard Gold', '111 Inwood St.',95124, '312-883-7337'); insert into customer values (23514, 'Robert Smith', '54 Gate Dr.',95388, '206-832-1221'); insert into customer values (23515, 'Christopher David', '777 Loto St.',98225, '360-458-9878'); insert into customer values (23516, 'Adam Beethoven', '234 Park Rd.',95380, '209-546-7299'); insert into customer values (23517, 'Ludwig Bach', '5790 Walnut St.',95382, '209-638-2712'); insert into customer values (23518, 'Kathleen Pedersen', '1233 Federal Ave E', 98102, '360-573-7239'); insert into salesOrder values (1020, 23511, 'P0239403', '2018-01-13', '2018-01-15'); insert into salesOrder values (1021, 23513, 'P0239401', '2018-01-13', '2018-01-16'); insert into salesOrder values (1022, 23513, 'P0239402', '2018-01-15', '2018-01-17'); insert into salesOrder values (1023, 23512, 'P0239403', '2018-01-16', '2018-01-18'); insert into salesOrder values (1024, 23511, 'P0239402', '2018-01-18', '2018-01-20'); insert into salesOrder values (1025, 23511, 'P0239403', '2018-01-29', '2017-01-31'); insert into salesOrder values (1026, 23512, 'P0239404', '2018-01-30', '2018-01-31'); insert into salesOrder values (1027, 23512, 'P0239402', '2018-01-30', '2018-01-31'); insert into salesOrder values (1028, 23512, 'P0239404', '2018-01-30', '2018-01-31'); insert into salesOrder (ONO, CNO, ENO, RECEIVED) values (1029, 23513, 'P0239402', '2018-01-31'); insert into salesOrder (ONO, CNO, ENO, RECEIVED) values (1030, 23511, 'P0239401', '2018-01-31'); insert into orderLine values (1020, 10501,7); insert into orderLine values (1020, 10502,15); insert into orderLine values (1020, 10504,3); insert into orderLine values (1020, 10503,6); insert into orderLine values (1021, 10605,4); insert into orderLine values (1022, 10605,2); insert into orderLine values (1022, 10704,4); insert into orderLine values (1023, 10879,4); insert into orderLine values (1023, 10988,19); insert into orderLine values (1024, 10502,7); insert into orderLine values (1024, 10988,2); insert into orderLine values (1025, 10502,4); insert into orderLine values (1025, 10988,3); insert into orderLine values (1025, 10948,2); insert into orderLine values (1026, 10965,15); insert into orderLine values (1026, 10933,5); insert into orderLine values (1027, 10933,21); insert into orderLine values (1028, 10933,9); insert into orderLine values (1028, 10965,11); insert into orderLine values (1029, 10933,4); insert into orderLine values (1029, 10965,10); insert into orderLine values (1029, 10988,3); insert into orderLine values (1030, 10965,6); 功能：

image

Answer 2

由于我没有找到解决此问题的方法，因此我创建了一个R包并使其在CRAN上可用。如何获取此信息的示例：

# Install package
install.packages("bwimage")

# Load package
library("bwimage")

# Path to an example provided by bwimage package
bush<-system.file("extdata/bush.JPG",package ="bwimage") 

# Convert the image to a binary matrix. For each pixel, the intensity of red, green and blue is averaged and compared to a threshold. If the average intensity is less than the threshold (default is 50%) the pixel will be set as black (1 in the matrix), otherwise it will be white (0).

threshold_color(bush,"jpeg", "frame_fixed",target_width = 15,target_height=15)