diff --git a/floatimg.h b/floatimg.h
index 2de8bd4..e3bf0d5 100644
--- a/floatimg.h
+++ b/floatimg.h
@@ -4,7 +4,7 @@
  *	http://la.buvette.org/photos/cumul
  */
 
-#define		FIMG_VERSION	160
+#define		FIMG_VERSION	161
 
 /*
  *	in memory descriptor
@@ -223,6 +223,7 @@ int   fimg_to_gray(FloatImg *head);
 int   fimg_add_cste(FloatImg *fi, float value);
 int   fimg_mul_cste(FloatImg *fi, float value);
 int   fimg_ajust_from_grab(FloatImg *fi, double maxima, int notused);
+int   fimg_absolute(FloatImg *fimg);
 void  fimg_drand48(FloatImg *fi, float kmul);
 long   fimg_count_negativ(FloatImg *fi);
 long   fimg_clamp_negativ(FloatImg *fi);
diff --git a/lib/fimg-math.c b/lib/fimg-math.c
index d6fd10c..33073e4 100644
--- a/lib/fimg-math.c
+++ b/lib/fimg-math.c
@@ -1,5 +1,5 @@
 /*
- *		fimg-core.c
+ *		fimg-math.c
  *
  *
  */
@@ -295,6 +295,22 @@ fimg_mul_cste(fi, coef);
 return 0;
 }
 /* ---------------------------------------------------------------- */
+int fimg_absolute(FloatImg *fi)
+{
+int		surface, idx;
+
+surface = fi->width * fi->height;
+
+for (idx=0; idx<surface; idx++) {
+	fi->R[idx] = fabsf(fi->R[idx]);
+	fi->G[idx] = fabsf(fi->G[idx]);
+	fi->B[idx] = fabsf(fi->B[idx]);
+	}
+
+return 0;
+}
+/* ---------------------------------------------------------------- */
+
 /*            Warning: this function is _very_ slow                 */
 void fimg_drand48(FloatImg *fi, float kmul)
 {
diff --git a/tools/fimgfx.c b/tools/fimgfx.c
index 41cf254..869e9f2 100644
--- a/tools/fimgfx.c
+++ b/tools/fimgfx.c
@@ -27,7 +27,8 @@ typedef struct {
 enum fxid { Fx_cos01=5, Fx_cos010, Fx_pow2, Fx_sqrt, Fx_gray0, Fx_halfsz0,
 		Fx_rot90, Fx_cmixa, Fx_desat, Fx_ctr2x2, Fx_norm,
 		Fx_classtrial, Fx_mirror, Fx_shift0, Fx_trimul,
-		Fx_xper, Fx_binarize, Fx_trinarize,Fx_hilight_R };
+		Fx_xper, Fx_binarize, Fx_trinarize, Fx_hilight_R,
+		Fx_absolute };
 
 Fx fx_list[] = {
 	{ "cos01",		Fx_cos01,	0,	1 },
@@ -49,6 +50,7 @@ Fx fx_list[] = {
 	{ "binarize",		Fx_binarize,	0,	1 },
 	{ "trinarize",		Fx_trinarize,	0,	1 },
 	{ "hilightr",		Fx_hilight_R,	0,	1 },
+	{ "abs",		Fx_absolute,	0,	0 },
 	{ NULL,			0,		0,	0 }
 	};
 
@@ -231,6 +233,10 @@ switch (action) {
 		foo = fimg_highlight_color(&src, &dest, 'R', 1.333);
 								break;
 
+	case Fx_absolute:
+		fimg_copy_data(&src, &dest);
+		foo = fimg_absolute(&dest);
+								break;
 	default:
 		fprintf(stderr, "%s %s : %d is bad action\n",
 					__FILE__, __func__, action);