Image quality

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Wed, 2007-02-14 13:30
vikas_bansal
Joined: 2005-02-12
 Forum posts: 98
I am using on board camera API.

I am taking snap of 640x480 and using EFormatFbsBitmapColor16M in CCamera::PrepareImage, I am getting image of size 15 kb .

but when e using native camera and using it's setting reolution=640x480 and quality =Maximium, when i take snap by native camera app then i get image of size 70 kb around (i.e better quality)

My question is that how can i ipmrove jpeg quality in my application. ?
Please suggest


Thu, 2007-02-15 00:41
eric
NewLC AdministratorSymbian AccreditedForum Nokia Champion
Joined: 2003-01-14
 Forum posts: 2009
Re: Image quality
Use CCamera::SetJpegQuality()

Eric Bustarret
NewLC Founder & CEO / Professional Symbian OS Consultant

 
Thu, 2007-02-15 06:09
vikas_bansal
Joined: 2005-02-12
 Forum posts: 98
Re: Image quality
Hi Eric,Thanks for reply
I already tried to use it before calling CCamera::PrepareImage but i gvae no effect where should i use it?
what value i should give to it 99 or any other to get the maximum quality.
 
Thu, 2007-02-15 07:52
janza
Joined: 2004-10-18
 Forum posts: 40
Re: Image quality
You are using bitmap format (EFormatFbsBitmapColor16M) for the images you capture using Camera API. With those the JPEG quality does not really affect anything, since the images are not JPEGs. I assume that you encode the image after the capture, so maybe you should change the quality setting of the JPEG encoder?

The other solution is to capture the images in EFormaExif and use the JPEG quality setting of Camera API.

Anyway, file size of JPEG file depends on the image content, so you should not compare the quality of the captured images only by comparing the file size...
 
Fri, 2007-02-16 08:41
vikas_bansal
Joined: 2005-02-12
 Forum posts: 98
Re: Image quality
thanks for reply.

Yes I know the size depends upon content.
I take care of this . And i am not talking about 2-5 KB I am talking about difference of 80 KB size .I get  jpg image of size 80-100 KB from 6680 having sze 640x480 with high quality on from native Camera Application.While My app only takes of 15-20 KB of same content.
Details of both images are same.

so far I am only able to produce 15-20 KB with all possible Enums used in CCamera::PrepareImgeCapture().

Do I need to do some image processing to improve it's quality .

I am getting JPEG in HBUFC8* of IMageReady where i am also getting CFBSBitmap* , So i don't need to convert to jpeg but i also tried to convert it by using CImageIncoder then also iam geetiing sam,e quality Image.

Please tell me where Should i Use CCamera::setJpegQuality and what value , i should give
 
Mon, 2007-02-19 08:14
janza
Joined: 2004-10-18
 Forum posts: 40
Re: Image quality
Call PrepareImageCapture with format EFormatExif and call SetJpegQuality with some reasonable value like 75. Then call CaptureImage. There is no point in setting the quality to 100, you will get bigger files, but the subjective quality does not get that much better.

Do you think that there is something wrong with the image quality in the first place? I mean just by looking at the image, not by comparing the file size? Can you post the image you have captured so that I can take a look?
 
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