how to display the image

I have downloaded the SPHIT code and i displayed a frame from a video which ins i avi format

clc
clear all

nFrame=1;

filename=('rhinos.avi');
Y_new = SPIHT_main(nFrame,filename)
imshow(Y_new)

but the image is not displayed clearly it just consists of white and black

please tell how to display the image

Answer 1

[Walter Roberson]

Experiment with

imshow(Y_new,[])

[nkumar]

even now image is not displaing it is black with gray

[Walter Roberson]

Please show

class(Y_new)
max(Y_new(:))
min(Y_new(:))

[nkumar]

 class(Y_new)=double
max(Y_new(:))= 240.0000
min(Y_new(:))= -7.6415e-11