I didn't know phantasia was a thing until recently. Intrigued by the concept I started trying to see if I could turn on this mind's eye. I'm getting to the point where I can induce something like the hypnopompia you describe. With my eyes closed I can "see". It's a wonderful and strange sensation. I can only do it for a few seconds at a time before a sense of vertigo forces my mind's eye shut. I'm hoping to get better control with practice. I'll try and describe the process I use. Maybe others will find it useful or interesting.  In a quiet, safe place, where you won't be disturbed, close your eyes and clear your mind. Absorb the black. Feels its texture. See the noise. Picture a point. Just a dimensionless point - a fixed location in the black. Try and move around the point. Above, around, below. Even this first step can be scary the first time. Now imagine as you move around the point, you become aware that there's a second point behind the first one, connected by a line. Examine this line from all directions. See its length. See how the perspective changes as you move around it. When you're comfortable around the line, add a third point; making a triangle. For the first time there's something to actually "see". From all directions, see its surface. Look at its colour. Feel its texture. You can even try and touch it with a finger. If you manage this, look at your hand and be amazed that you can see it with your eyes closed. Behind the triangle, and another point, creating a solid tetrahedron pyramid that becomes visible as you move around the triangle. Now you have a solid object. Play with its size, feel its weight. Move around it or turn it over in your hand. Finally, become aware that the object is simply part of a larger scene: a toy on the ground; part of a roof; a pyramid in Giza. Look up. Look and move around. Look at the scene, taking in the colours and textures. You've turned on your mind's eye!  It's usually at this point where my heart skips a beat like I'm falling over backwards. My mind's eye slams shut and yanks me back to reality. Sorry for the long reply but I hope someone finds it useful. 

I didn't know phantasia was a thing until recently. Intrigued by the concept I started trying to see if I could turn on this mind's eye. I'm getting to the point where I can induce something like the hypnopompia you describe. With my eyes closed I can "see". It's a wonderful and strange sensation. I can only do it for a few seconds at a time before a sense of vertigo forces my mind's eye shut. I'm hoping to get better control with practice. I'll try and describe the process I use. Maybe others will find it useful or interesting.  In a quiet, safe place, where you won't be disturbed, close your eyes and clear your mind. Absorb the black. Feels its texture. See the noise. Picture a point. Just a dimensionless point - a fixed location in the black. Try and move around the point. Above, around, below. Even this first step can be scary the first time. Now imagine as you move around the point, you become aware that there's a second point behind the first one, connected by a line. Examine this line from all directions. See its length. See how the perspective changes as you move around it. When you're comfortable around the line, add a third point; making a triangle. For the first time there's something to actually "see". From all directions, see its surface. Look at its colour. Feel its texture. You can even try and touch it with a finger. If you manage this, look at your hand and be amazed that you can see it with your eyes closed. Behind the triangle, and another point, creating a solid tetrahedron pyramid that becomes visible as you move around the triangle. Now you have a solid object. Play with its size, feel its weight. Move around it or turn it over in your hand. Finally, become aware that the object is simply part of a larger scene: a toy on the ground; part of a roof; a pyramid in Giza. Look up. Look and move around. Look at the scene, taking in the colours and textures. You've turned on your mind's eye!  It's usually at this point where my heart skips a beat like I'm falling over backwards. My mind's eye slams shut and yanks me back to reality. Sorry for the long reply but I hope someone finds it useful.