Hi,

Hiding i bit in each byte or one bit in whole image? I guess you are hiding one bit in each byte. This is very old and easier method of hiding. If you are doing some research work then I will suggest you to go for latest techniques for steganography. Rather methods are nearly similar for watermarking and steganography. You can refer my research papers. Only the aim of both hiding techniques is different.

Ideal value of PSNR should be infinity so higher the PSNR better will be the technique.

Stegnography method by updating LSB is less secure one and traditional method. Even though if you are updating the LSB bit the PSNR will depend on the pixel intensity change from original image and the image that we will get after updating. The best PSNR is infinity will get when there is no difference between original image and modified image. So here it's obvious that the PSNR will purely dependent on your information bits that which you are going to add on the LSB for hiding purpose.

dear Gusharanjeet Singh Kalra thank you for your response

i know when the psnr value is large that means a good image quality. some time the psnr values come a large based on the nature of the image.

i hide one bit in some location of cover image depending on a new hiding algorithm.

i read a lot of papers talking about hidden one bit in byte ,and the experimental result of papers give the psnr values between (70 to 80)dB .now i want to compare my algorithm against another to compute the effectiveness depend on the psnr value.

my algorithm give values of psnr more than 80 dB.

Dear Manikandan Vm thank you for your response

All the words that you said is true.

Image quality assessment metrics suggested by previous contributors are MSE and PSNR. These metrics are simple to calculate,mathematically convenient, and have clear physical meanings.  However these IQ assessments lack two critical features: 1) Ability to image similarity across stego image of varying distortion types; 2.) They are not very well matched to perceived visual quality. A new approach to assess image quality independent of the type and size of pixel size of concerned stego images is the estimation of Structural Similarity indices using  Structural Similarity Index metric(SSIM)

The author might need to see our investigation of SSIM computation of dissimilar stego images in secure e-voting application in this link:

https://www.academia.edu/6371423/Performance_Evaluation_of_modified_Stegano-Cryptographic_model_for_Secured_E-voting

Ideal value of PSNR should be infinite which is not possible. PSNR with 53 for 100% embedding(1bit / pixel) is treated as excellent. Generally for standard algorithms, PSNR value should be 50 and above for 100% embedding(1bit / pixel) in Lena image (as cover image.) 

That means you are hiding only one bit somewhere in the whole image? If it is so, then PSNR of 80 dB is much less. But before I will comment more, I want more information about your embedding method and objective of your work.

dear Olaniyi Olayemi Mikail thank you so much for your response.

The Structural similarity(SSIM) index is a method for measuring the similarity between two images. The SSIM index can be viewed as a quality measure of one of the images being compared, provided the other image is regarded as of perfect quality. 

the SSIM is giving values betwwen (-1 to 1),if the value is near to 1 that means the test images(cover image, stego image) is more alike and vice versa.

dear Amitava Nag thank you for your response.

I totally agree with you.

Dear Gusharanjeet Singh Kalra thank you for your response again.

No, I hide stream of bits (message) in cover image, bit after the other.

the methodology of my method based on randomization to gives a good robust against the attacker .

the objective of my work as illustrated in the following:

1- load large payload information in cover image.

2- my algorithm must be more secure against the any attacking.

3- the quality of stego image must be high.

Hi, All your objective are contradictory to each other. For an example, if you try to increase your payload, then your quality of the image is going to be reduced. Though your third aspect of being secured against attacks is also dependent on the depth of the bit embedded.

On the other hand, if you want to increase the quality of your stego image then you have to either reduce the payload or depth of the bit to be embedded.

So you have to make a trade off between payload/quality and security.

I am also sending you one screen shot of a book which shows the relation between these three parameters. It is from:

A.Hanjalic, G.C.Lngelaar, P.M.B.van Roosmalen, J. Biemond and R.L. Lagendijk, Image and Video Databases: Restoration, Watermarking and Rerieval, Elsevier Science B.V., 2000.