Fade child object with a coroutine

Hi, I've got a problem when trying to fade my child object in a coroutine.

Here is my code :

 IEnumerator fadeOutCoroutine()
     {
         Debug.Log("Coroutine fade out");
 
         if (m_parent == null)
         {
             setParent();
         }
 
         int target = (int)Mathf.Round(m_fadeDuration * Application.targetFrameRate);
         Debug.Log("Target ; " + target);
 
         for (float frame = 0; frame <= target; ++frame)
         {            
             foreach (Image image in m_parent.GetComponentsInChildren<Image>())
             {
                 if (objectTofade(image.gameObject.name))
                 {                
                     image.color = new Color(image.color.r, image.color.g, image.color.b, 1 - (frame / target));
                     Debug.Log(image.gameObject.name + " : " + image.color.a, image.gameObject);
                 }
             }
 
             yield return new WaitForEndOfFrame();
 
         }

objectToFade only say if I have to fade the current object.

The output of my debug.log is ok : the value is correct from 1 to 0, but my object is not fading.

Does anyone know what I've done wrong ?

Thx by advance,