topic Re: Reading a 32 bit image in LabVIEW

Reading a 32 bit image

AnoopV — Wed, 20 Jun 2012 08:55:27 GMT

Hello Everybody

I have few 32 bit images and i need to read that 32 bit images in LabVIEW and display or perform further processing .

I am unable to read 32 image using funtion

This gives me blank image output .

After this attempt , i have tried with below code

When i probe at the output of "Read PNG File.vi" i get the correct image but once i unflatten and converted to 24 bit , it gives me a blank image.

One of the example imput image is given below. Most of the vision functions deal with 24 bit images. Can anyone help me in this regard ?

Re: Reading a 32 bit image

GuenterMueller — Wed, 20 Jun 2012 09:12:53 GMT

Look at the example named "ReadFile Example" that ships with the Vision Development Modul. This example supports reading color images from disk.

Re: Reading a 32 bit image

AnoopV — Wed, 20 Jun 2012 10:13:46 GMT

No that will not work for me. I am able to read 24 bit RGB images. I wanted to read 32 bit images

Re: Reading a 32 bit image

GuenterMueller — Wed, 20 Jun 2012 10:51:34 GMT

What type of 32bit image do you have? You know about the available image types in NI Vision?

Re: Reading a 32 bit image

AnoopV — Wed, 20 Jun 2012 10:56:46 GMT

The image i have is 32 bit RGB+Alpha layer.

I have shared the attachement here. Pls check it , its bit depth is given as 32 bit where as normal images has 24 bit depth

If I open the image (Attached) in MS Paint , it will display as black box without any white pixels.

Re: Reading a 32 bit image

GuenterMueller — Wed, 20 Jun 2012 12:38:52 GMT

Yes, you are right. This image type is not supported. (I am no here in image types as I usually use a camera to get one.) Where did you get the image from? Is there a chance to convert it to a supported type?

Re: Reading a 32 bit image

AnoopV — Wed, 20 Jun 2012 12:57:20 GMT

I got the images from project customer. I have already an application which reads RGB images which has bit depth 24 bits and display / perform further image processing.

Do you have any idea how to convert 32 bit images to 24 bit images without the help of LabVIEW? I have successfully converted one 32 image to 24 bit image using GIMP. But i have lots of images like this, it cauese lot of manual work.

Re: Reading a 32 bit image

Javed_H — Wed, 20 Jun 2012 13:00:02 GMT

Hi Anoop,

There is a some kind of scripting available in GIMP. You can use that for batch conversion.

Regards

Javed

Re: Reading a 32 bit image

DFGray — Wed, 20 Jun 2012 15:32:59 GMT

ImageMagick may be a better choice. It is leaner and designed for command line use, so you can call it from LabVIEW easily. It also supports batch operations on the command line. This assumes it supports your image type (it probably does).

Re: Reading a 32 bit image

GregSands — Wed, 20 Jun 2012 21:47:50 GMT

I'd also vote for trying ImageMagick - I've called it from LabVIEW (using System Exec.vi) with good results.

Re: Reading a 32 bit image

rolfk — Thu, 21 Jun 2012 07:00:11 GMT

I would not even bother with external tools. It's trivial enough to detect the 32 bit depth of an image when using the Read PNG File.vi and then removing the Alpha channel, effectively creating a 24 bit image. You probably will want to use the extracted alpha channel to mask out the color pixels appropriately.

Re: Reading a 32 bit image

zou — Fri, 22 Jun 2012 23:56:52 GMT

If you take a close look of this image, all 3 channels (R, G, B) are just 0. Which is a black image.

All the information is in the alpha channel.

So forget about the 0s, just use the alpha channel, you can get the 24bit image like this: