How To Count Black Pixels In A Bitmap
Apr 19, 2009
My goal is to iterate through each pixel determining whether it is black or white. Ideally I want to do this one row at a time (so I can count the number of black pixels in each row). This is a bitonal image.I tried to get it started, but I don't understand what value(s) I'm supposed to be polling for. The following code takes a stab at it (i.e. makes a guess as to what value I'm supposed to check) and then outputs that value to a textfile.When I read the textfile, though, it doesn't look like anything useful.This code is an attempted modification of some code found in a CodeProject article.[code]
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Jul 27, 2009
I'm trying to make a -what i thought would be simple app.My intention was to build program that:1) i'd provide a grayscale image2) the program would count the black pixels the grey pixels the more grey pixels etc. (the hue) and the white3) would make the percentage sum of all pixels, that is: 300.000 black pixels (rgb 0 0 0) etc. given that 0 is the black, 100 the white. e.g a simple grayscale image is 55.2 white
This was my way and i don't think that is useful:
First of a button to convert the image to greyscale:
Dim bm as new Bitmap(source.Width,source.Height)
Dim x
Dim y
[CODE]...
Secondly, -and that's the stupid way- i did -or better i wanted to do- this: i put the code to dynamically create labels, each label having the colour of a pixel as background colour and as text the colour converted to rgb
The third step which i intended to do (i couldn't get pas two) was to sum up the labels etc.
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Jul 12, 2010
is there anyway i could count the number of say Black pixels in my picturebox say i have a picture in it that has 1 black pxiel i would like to to but that to a string so i could put it in a textbox or a msgbox like this
so in RGB black would be 0-0-0 but how would i have it scan the pixtuebox and count how many pixels show up with the rgb color 0-0-0
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Jan 31, 2012
I see that the Line method is replaced with DrawLine, however; it seems like DrawLine must treated as an object as follows:
Private Sub Form1_Paint(ByVal sender As Object, ByVal e _
As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
Draw a solid black line 25 pixels from the top of the form.[code].....
When I attempt to use this code (call it), I must somehow bring about an event, but I haven't found how to do that.How do I "call" this sub?
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Jun 21, 2012
i want to create image with width and height 64 and set all pixels to black
dim b as bitmap
b.width = 64
b.height = 64
[code]....
the code not working
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Aug 28, 2009
Was just wondering if there is a way to quickly clear all pixels in a bitmap without creating a new one?
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Feb 13, 2012
i mostly use C and assembly, but i thought i would give VB.NET a shot. i used to use VB6 all the time, so wanted to see how different this is. in VB2010, i'm trying to modify the pixels of a Bitmap object and then make it show up in a PictureBox on the form. i get no errors, but this code does not show the new bitmap after it runs.."disp" is the name of the PictureBox on the form.[code]
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Feb 14, 2012
Pretty self-explanatory question. I'm trying to see if I can do sprite animation in Visual Basic and, while I can use a Graphics object to translate a bitmap down a few pixels, I have absolutely no idea how to erase the bitmap drawn in its former position. Is there any way to erase the old image before the new image is drawn onto the form?
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Mar 10, 2011
I have scanned a few img's on 600 DPI. When i load them into a Bitmap class They have Vertical and Horizontal Resolution of 96 PPI To my calculation that is very close to 38 Pixels per centimeter. Now the image that I scanned is 4.5 Centimeter (1.77165354 Inch) In Diameter but When I measure It the 4.5 cm img is close to 1080 pixel in Diameter which is 240 Pixels/Centimeter (609.6 Pixels/inch) What is the correct way to get the actual Pixels per inch/centimeter from a bitmap or was it set incorrectly by my scanner ?
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Dec 7, 2010
I have a little piece of code which saves a certain Bitmap to a JPG image. The Bitmap is "composed like this" ( Ppiechart is a picturebox):[code]So After it is declared I start to do some drawing on this bitmap. And then I want to save it like this:[code]So this saves the image. But the problem is that the background of the image turns black when I open the file on my PC.The background of the Bitmap in the program itself is white. So does anybody have an idea what may cause this? Do I have to declare a color for the "mybitmap"?
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Mar 12, 2009
When I create a new bitmap the file is black. How do I make it white?
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Feb 19, 2006
I've been trying to mess around with image recognition in C# for some time now. But to do that, I need acces to all the pixels in the bitmap individually. At the moment, I'm using getPixel and setPixel. It works, but it's VERY slow. Is there any faster way to acces pixels in a bitmap? Unsafe code maybe?
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Oct 9, 2009
I need to write a code to find identical adjacent pixels in a bitmap image. It should work as the 'magical wand' in Photoshop. My images are always black and white (white background with car parts drawed in black). Given the x,y coordinate for a single black pixel in the whole image, the code should find (and paint with another color, say red) all other black pixels that are linked to that one, and so on, until all linked black points will be painted in red.
[Code]...
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Aug 12, 2011
I need to write a code to find identical adjacent pixels in a bitmap image. It should work as the 'magical wand' in Photoshop.My images are always black and white (white background with car parts drawed in black). Given the x,y coordinate for a single black pixel in the whole image, the code should find (and paint with another color, say red) all other black pixels that are linked to that one, and so on, until all linked black points will be painted in red.This way, suppose that I have an image with 4 car parts drawed, then if I give the x,y coordinate of a black pixel, just THAT part to whose the black pixel belongs to should be painted in red. All other parts will remain black. Does it make sense?At the end, there are two pictures (before and after) to help understanding what I need to do to the images.I tried a simple 8-pixel adjacent approach for every pixel (starting on initial coordinate) but it turns out into a very stupid and endless looping algorhitm.
Code:
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms
[code]....
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Jul 3, 2011
I'm using Bitmap to show picture box like slideshow using Timer. For each timer interval, I've to go for new instance of Bitmap, there System memory increases to 1MB, How to resolve this, 'BG is picture box
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tic Dim img As Bitmap
img = New Bitmap(System.Drawing.Bitmap.FromFile(FileIO.FileSystem.GetFiles
[CODE]...
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Dec 15, 2010
I'm trying to use a ToolTip directly to a Bitmap Object (System.Drawing.Bitmap), aparently I can't do this because Bitmap isnt a Windows Control.
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Sep 17, 2011
how can i create a monochrome bitmap from a semi transparent bitmap in vb.net? the bmp is for a transparency mask image for an icon i'm trying to create with the CreateIconIndirect API function.
i'm using vb2008 .Net3.5, but i would prefer an answer that would also work in vb2005
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May 26, 2011
Here is a short program to demonstrate my question. I just want to extraxct a rectangle bitmap from a big bitmap.Code as follows:
Private
Sub Button3_Click(ByVal sender
As System.Object,[code]....
Execution stops when hitting the Dim cloneBitmap statement, which should have created a bitmap out of the rectangle cut out.The message is:
"MissingMemeberException was unhandled.
No default member was found for type 'bitmap"
I just don't get it. Seems that the method Clone(Rectangle, PixelFormat was not found.
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Feb 10, 2010
I have a grass image located here in my directory. I want to just create a Bitmap, but I am getting an error. (Parameter is not valid.) Immediate Window: A first chance exception of type 'System.ArgumentException' occurred in System.Drawing.dll
[URL]
private void Form1_Load(object sender, EventArgs e)
{
Bitmap bmp = new Bitmap("grass.jpg");
}
bertino
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Feb 28, 2009
i have a problem with the Size in VB.Net I think the Control Size in VB.Net Is Pixels so I want to enter this size cm/inch
I want To Convert Pixels to cm/inch or cm/inch to Pixels
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Nov 2, 2010
I have added a column to a Datatable called CallsPerDay which is there to tell me how many telephone calls have been made on a particular day or days.Is there a datacolumn.expression which will allow me to Filter on the day, count the rows and then populate this added column with the result.
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Jul 16, 2010
I have some reports that I use with the MS ReportViewer and I need to get a count of the physical pages (as opposed to logical page count) to use with a print dialog. I've implemented a workaround so the ReportViewer control displays the correct number of physical pages, but is there a way to get that value from the ReportViewer control? The only publicly accessible property gives the logical page count.
[Code]...
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Feb 18, 2011
Basically, Is it possible to get a grids row count using jquery.if my grid has 20 rows in it not including the header or footer, i want to now the count of actual rows, this will tell my users how many tasks they have in their list.
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Dec 10, 2010
designing a Windows based computer program that will allow a user to enter some number (n) and a choice of a count up or count down for that many numbers. So for example, the user enters 5 as their number and selects the count down option, the message box displayed would contain the message: "Here are your numbers: 5,4,3,2,1,0"
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Oct 1, 2011
This is what I have, but It doesn't work with strings for some reason (only text files):
[Code]...
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Jul 5, 2009
I am looking for a way to count words in VB My full code is as follows Public Class lblTranslator
[Code]...
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Oct 6, 2010
Declare some class level variables that will keep track of the sums for each column. For example:
[Code]....
During the RowDataBound event, retrieve the data from each column and add it to the appropriate sum. I'm not sure if you are developing an ASP.NET application or a Win-forms desktop application so I cannot help you any further at this point. What have you tried so far to solve the problem?
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Oct 1, 2011
The code below reads an Icon from an .ico file, converts the Icon read to a Bitmap and saves the bitmap using:
Bitmap.Save(PathA)
Then does:
PanelShowWrittenIconA.BackgroundImage = New Bitmap(PathA)
[code].....
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Mar 31, 2009
this its a very silly problem i have with CheckBoxList control, i dont know if its just me or what but the whole idea of the control its just great but the implementation its very confusing.
im trying to eval something like this
if CheckBoxList.Items.Item(CheckBoxList.Items.Count-1).Checked=true then.....
or something like
CheckBoxList.CheckedItems.Item(CheckBoxList.Items.Count-1) = Checked then...
the problem its that i dont know how does the checkboxlist works but it just sucks that they had to make it so confuising....
i've handled lots and lots of collection controls and they all work in a similar and simple
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Oct 16, 2009
i`m trying to find in cm or mm the area of a frame (capture image).The picturebox has dimensions height:456 and width:553 PIXELS.So the total number of pixels are 456 x 553 = 252,168
If i compare image 1 with image 2 i can locate and draw a rectangle around that area of pixels that are different.i can get the width and the height of this rectangle in PIXELS.e.g Height:49 Width:33 PIXELS
How can i covert these into cm or mm. What i need to know for the conversion?
I know dpi: dots per inch but what`s the value for my rectangle?
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