How to recognize negative numbers with OCR?

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sasad games 2021-2-27

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/757939-how-to-recognize-negative-numbers-with-ocr

评论： sasad games 2021-2-27

I am using the following code to recognize numbers in images and transform it to values. However, it only recognizes positive values. Can you please help me to modify the code in order to be able to identify positive and negative values? Thanks in advance.

clc
clear all
close all
%%
I=imread('N1.png'); 
I2=I(:,:,3);
I3=ind2rgb(I2,gray);
I4=imcomplement(I3);
N=Im_text(I4);
function [val] = Im_text(Original) 
        % Increase image size by 3x
        my_image = imresize(Original, 3);
        % Localize words
        BW = imbinarize(rgb2gray(my_image));
        BW1 = imdilate(BW,strel('disk',6));
        s = regionprops(BW1,'BoundingBox');
        bboxes = vertcat(s(:).BoundingBox);
        % Sort boxes by image height
        [~,ord] = sort(bboxes(:,2));
        bboxes = bboxes(ord,:);
        % Pre-process image to make letters thicker
        BW = imdilate(BW,strel('disk',1));
        % Call OCR and pass in location of words. Also, set TextLayout to 'word'
        ocrResults = ocr(BW,bboxes,'CharacterSet','.0123456789','TextLayout','word');
        words = {ocrResults(:).Text}';
        words = deblank(words);
        val=str2double(words);
end

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Answer 1

Image Analyst 2021-2-27

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/757939-how-to-recognize-negative-numbers-with-ocr#answer_634979

编辑：Image Analyst 2021-2-27

在 MATLAB Online 中打开

N1.png

Can't you simply add a - to the CharacterSet? Then if the first character is a -, it's a negative number.

This works fine:

grayImage = imread('N1.png');
if ndims(grayImage) == 3
	grayImage = rgb2gray(grayImage);
end
imshow(grayImage, 'InitialMagnification', 400);
axis('on', 'image');
N = Im_text(grayImage)
caption = sprintf('The number in here is %f', N);
title(caption, 'FontSize', 20);
%==================================================================================
function [val] = Im_text(Original)
% Increase image size by 3x
my_image = imresize(Original, 3);
ocrResults = ocr(my_image, 'CharacterSet', '-.0123456789', 'TextLayout', 'line')
words = {ocrResults(:).Text}';
words = deblank(words);
val = str2double(words);
end